Battle of the behinds! Pregnant Kim Kardashian bumps into bootylicious pal Serena Williams in London... as the tennis ace strokes her growing baby bump

Her second pregnancy has so far led to little change in her wardrobe.

And Kim Kardashian chose another revealing look on Friday before bumping into her old friend Serena Williams who couldn't resist touching the star's growing belly. 

The bootylicious ladies embraced on the street outside Harrods and Kim placed her hands on her hips as the World Number One tennis player rubbed her baby bump.

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Shape shifters: Kim Kardashian bumped into her old friend Serena Williams who couldn't resist touching the star's tummy

Shape shifters: Kim Kardashian bumped into her old friend Serena Williams who couldn't resist touching the star's tummy

The Keeping Up With the Kardashians star, 34, who is expecting a baby boy later this year, dressed for the London heat in her plunging outfit. 

She showed plenty of cleavage in a low-cut black top and ruffled skirt.

In stark contrast Serena embraced the sporty look in a white and purple Nike tank paired with skin-tight grey leggings and trainers just days before the start of Wimbledon.

Growing belly: Kim seemed to be touched at the middle as the tennis ace paid reference to her bump

Growing belly: Kim seemed to be touched at the middle as the tennis ace paid reference to her bump

Bump watch: Kim placed her hands on her hips as the World Number One tennis player rubbed her tummy

Bump watch: Kim placed her hands on her hips as the World Number One tennis player rubbed her tummy

Take your style up a tier in Kim's ruffled skirt

They say if it ain't broke don't fix it and Kim Kardashian has stuck to this mantra faithfully. The Selfish author rocked her signature look in a black, plunge neck top and form fitting skirt by one of her favorite brands, Givenchy.

The reality star added a pair of perspex sandals and dark shades to complete her racy ensemble.

We love the girly asymmetric ruffle along the waistline of Kim's form fitting number that can easily transition from day to night. Dress it up with a floral print blouse and classic black pumps for the office.

Steal Kim's style by clicking right to get her skirt at Farfetch. Of course the luxury label comes with a pretty hefty price tag, so why not emulate the look with one of the options below? BCBG's version has a sexy side split and it's less than $100. How's that for smart shopping?

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Close friends: Kim and Serena joked and laughed together as they chatted outside Harrods 

Close friends: Kim and Serena joked and laughed together as they chatted outside Harrods 

Gentle: Serena carefully ran her hand over the Keeping Up with the Kardashians' star's belly

Gentle: Serena carefully ran her hand over the Keeping Up with the Kardashians' star's belly

Figure hugging: Both Serena and Kim wore form-fitting outfits which showed off their curves

Figure hugging: Both Serena and Kim wore form-fitting outfits which showed off their curves

Old friends: They embraced on the street outside Harrods in London 

Old friends: They embraced on the street outside Harrods in London 

Sporty look: Serena wore a white and purple Nike tank and dark grey leggings

Sporty look: Serena wore a white and purple Nike tank and dark grey leggings

Tender moment: Both women they posed for photographs outside Harrods

Tender moment: Both women they posed for photographs outside Harrods

Kim chose the revealing outfit amid rumours she'll head to Glastonbury today ahead of husband Kanye West's headline slot on Saturday night.  

The halter-neck number showed off some extreme cleavage while the beauty's trim waist was also accentuated thanks to her flattering long ruffled skirt from Givenchy

Kim accessorised with a pair of perspex heels, a favourite style of the fashion lover.  

Plunging: Pregnant Kim  put her curves in the spotlight as she left the Dorchester Hotel in London on Friday

Plunging: Pregnant Kim put her curves in the spotlight as she left the Dorchester Hotel in London on Friday

Head-turning: Kim was hard to miss thanks to her plunging top, with the star keeping the rest of her look simple

Head-turning: Kim was hard to miss thanks to her plunging top, with the star keeping the rest of her look simple

Va va voom: The 34-year-old, who is expecting a baby boy later this year, is showing no signs of hanging up her revealing wardrobe

Va va voom: The 34-year-old, who is expecting a baby boy later this year, is showing no signs of hanging up her revealing wardrobe

Curves: The halter-neck number showed off some extreme cleavage while the beauty's trim waist was also accentuated in the form-fitting piece
Curves: The halter-neck number showed off some extreme cleavage while the beauty's trim waist was also accentuated in the form-fitting piece

Curves: The halter-neck number showed off some extreme cleavage while the beauty's trim waist was also accentuated in the form-fitting outfit 

Kim kept the rest of her look simple with an elegant gold necklace and her favourite dark shades on as she headed out into the city sunshine.

The star left her dark locks loose and swept back from her face and accentuated her features with a nude lip colour.

A frill detail across her stomach and her outfit's asymmetrical cut meant any sign of Kim's baby bump was well hidden.  

Make way: The star was helped through the crowds, who were snapping pics on their camera phones, by a burly bodyguard

Make way: The star was helped through the crowds, who were snapping pics on their camera phones, by a burly bodyguard

VIP in town: Kim is added a pair of dark shades and left her long locks loose and swept back from her face
VIP in town: Kim is added a pair of dark shades and left her long locks loose and swept back from her face

VIP in town: Kim is added a pair of dark shades and left her long locks loose and swept back from her face

London calling: The reality star is showing little sign of her second pregnancy so far

London calling: The reality star is showing little sign of her second pregnancy so far

Flying solo: There was no sign of Kim's husband Kanye, with the rapper no doubt busy preparing for his anticipated headline slot on Glastonbury's Pyramid stage on Saturday night

Flying solo: There was no sign of Kim's husband Kanye, with the rapper no doubt busy preparing for his anticipated headline slot on Glastonbury's Pyramid stage on Saturday night

Supporting her man: Kim's stop in London has led to plenty of speculation she'll be heading down to Somerset to watch her husband perform

Supporting her man: Kim's stop in London has led to plenty of speculation she'll be heading down to Somerset to watch her husband perform

VIP treatment: Don't expect the glam star to be slumming it on the Glastonbury campsite with rumours circulating she'll fly in via helicopter

VIP treatment: Don't expect the glam star to be slumming it on the Glastonbury campsite with rumours circulating she'll fly in via helicopter

She was spotted shopping at luxury lingerie boutique Rigby & Peller.

Staff told MailOnline: 'She was an exceptionally nice customer, lovely and down to earth and welcome again in the boutique at any time!' 

The star was accompanied by a burly bodyguard as she made her way through the crowds gathered outside her London base and into a waiting car.

There was no sign of husband Kanye, with the rapper no doubt busy preparing for his anticipated headline slot on Glastonbury's Pyramid stage on Saturday night. 

Kim's stop in London has led to plenty of speculation she'll be heading down to Somerset to watch her husband, who's Glastonbury booking has proved somewhat controversial.

Festival wardrobe? Glam Kim might have to swap her heels for wellies if she heads to Worthy Farm, with rain forecast for the weekend
Festival wardrobe? Glam Kim might have to swap her heels for wellies if she heads to Worthy Farm, with rain forecast for the weekend

Festival wardrobe? Glam Kim might have to swap her heels for wellies if she heads to Worthy Farm, with rain forecast for the weekend 

Busy week: Jet-setter Kim isn't cutting back on her hectic schedule, with the star hitting Cannes earlier this week before heading to London

Busy week: Jet-setter Kim isn't cutting back on her hectic schedule, with the star hitting Cannes earlier this week before heading to London

Europe trip: Kim hit the MailOnline yacht party on Wednesday during the Cannes Lions festival

Europe trip: Kim hit the MailOnline yacht party on Wednesday during the Cannes Lions festival

Peace and love: Kim greeted the hoards of fans with camera phones as she made her way to her car

Peace and love: Kim greeted the hoards of fans with camera phones as she made her way to her car

Popular lady: There was a huge crowd waiting for Kim outside her city centre hotel

Popular lady: There was a huge crowd waiting for Kim outside her city centre hotel

Coming through: The star looked relaxed and flawless despite her busy week in Europe

Coming through: The star looked relaxed and flawless despite her busy week in Europe

Where to next? The mum of one is enjoying some time across the pond as she juggles her and Kanye's schedules

Where to next? The mum of one is enjoying some time across the pond as she juggles her and Kanye's schedules

Pregnancy certainly isn't slowing Kim down for after spending Wednesday partying on the MailOnline yacht in Cannes, she hit the town in London on Thursday. 

Kim, 34, reunited with Kanye in the English capital after he attended Men's Fashion Week in Paris while she was at the Cannes Lions Advertising Festival with her mother Kris Jenner and sister Kylie.

Kardashian dressed in an artfully ripped T-shirt for her night out at Hakkasaan with Kanye, with the garment showing off her ample cleavage again.  

Reunited: Kim and Kanye West reunited in London on Thursday after spending time in separate parts of France earlier this week

Reunited: Kim and Kanye West reunited in London on Thursday after spending time in separate parts of France earlier this week

Date night: Kanye attended Men's Fashion Week in Paris while Kim was at the Cannes Lions Advertising Festival with her mother Kris Jenner and sister Kylie but they reunited in London 

Date night: Kanye attended Men's Fashion Week in Paris while Kim was at the Cannes Lions Advertising Festival with her mother Kris Jenner and sister Kylie but they reunited in London 

A pencil skirt highlighted Kim's famous derriere while a belt drew attention to her still narrow waist. 

Kim completed her outfit with a pair of white strappy sandals and wore her long dark hair loose around her shoulders. 

Kanye appeared to be taking fashion tips from his wife, also opting for a plunging T-shirt, which he wore with ripped white jeans and a cardigan. 

Pregnancy wardrobe: Kim is sticking to the curve hugging outfits throughout her second pregnancy

Pregnancy wardrobe: Kim is sticking to the curve hugging outfits throughout her second pregnancy

Dressed to impress: Kim flaunted her ample assets in a ripped T-shirt which left little to the imagination

Dressed to impress: Kim flaunted her ample assets in a ripped T-shirt which left little to the imagination 

Not slowing down: Pregnancy certainly isn't slowing Kim down for after spending Wednesday partying on the MailOnline yacht in Cannes, she hit the town in London on Thursday

Not slowing down: Pregnancy certainly isn't slowing Kim down for after spending Wednesday partying on the MailOnline yacht in Cannes, she hit the town in London on Thursday

Looking rearly good: Kim showed off her ample assets and curvy derriere on her date night with Kanye
Looking rearly good: Kim showed off her ample assets and curvy derriere on her date night with Kanye

Looking rearly good: Kim showed off her ample assets and curvy derriere on her date night with Kanye 

While Kim arrived in London on Thursday morning via plane, Kanye took the Eurostar from Paris later in the day before making his way to their hotel for a reunion with his wife. 

Kim is expecting her second baby with Kanye but admitted she still hasn't decided how to introduce their two-year-old daughter North to her new sibling.

The pregnant star, who was one of the VIP guests at the MailOnline yacht party in Cannes, said she and her rapper husband read books to North that include stories about being a big sister.

Sexy and she knows it: A pencil skirt highlighted Kim's famous derriere while a belt drew attention to her still narrow waist

Sexy and she knows it: A pencil skirt highlighted Kim's famous derriere while a belt drew attention to her still narrow waist

Chic: Kim completed her outfit with a pair of white strappy sandals and wore her long dark hair loose around her shoulders
Chic: Kim completed her outfit with a pair of white strappy sandals and wore her long dark hair loose around her shoulders

Chic: Kim completed her outfit with a pair of white strappy sandals and wore her long dark hair loose around her shoulders

Back together: The couple were apart for a few days while they attended different events in France 

Back together: The couple were apart for a few days while they attended different events in France 

Holding on to her man: Kim held on to Kanye as the pair stepped out together in London 

Holding on to her man: Kim held on to Kanye as the pair stepped out together in London 

Can't resist: Kanye took a sneaky peek at his wife's derriere as he helped her into the car 

Can't resist: Kanye took a sneaky peek at his wife's derriere as he helped her into the car 

So in love: Kim and Kanye were friends for years before they finally started dating and now couldn't be happier
So in love: Kim and Kanye were friends for years before they finally started dating and now couldn't be happier

So in love: Kim and Kanye were friends for years before they finally started dating and now couldn't be happier 

Heading to the farm? Kim's reunion with Kanye in London could signal that the star will join her husband at Glastonbury festival over the weekend 

Heading to the farm? Kim's reunion with Kanye in London could signal that the star will join her husband at Glastonbury festival over the weekend 

Kim explained to MailOnline: 'I don't know if North really understands she's getting a baby brother yet.

'We read books at night with stories about big sisters, and baby brothers, families.

'I'm sure she'll come to the hospital and meet him, that's what Kourtney did with her kids so I'll take advice from her.'

Kim also revealed she plans to wear 'simple' maternity wear this time round.

She said: 'At this stage, I'm just trying to fit into the things that still fit me.

Fashion advice? Kanye appeared to be taking fashion tips from his wife, also opting for a plunging T-shirt, which he wore with ripped white jeans and a cardigan

Fashion advice? Kanye appeared to be taking fashion tips from his wife, also opting for a plunging T-shirt, which he wore with ripped white jeans and a cardigan

Separate travel plans: While Kim arrived in London on Thursday morning via plane, Kanye took the Eurostar from Paris later in the day before making his way to their hotel for a reunion with his wife

Separate travel plans: While Kim arrived in London on Thursday morning via plane, Kanye took the Eurostar from Paris later in the day before making his way to their hotel for a reunion with his wife

Big news: Kim is expecting her second baby with Kanye but admitted she still hasn't decided how to introduce their two-year-old daughter North to her new sibling

Big news: Kim is expecting her second baby with Kanye but admitted she still hasn't decided how to introduce their two-year-old daughter North to her new sibling

'I do think tighter clothes look better and more slimming, and I don't care how hot it is, I'm going to wear thin coats all summer to conceal my big arms.

'I'm going to have a strategy of just really simple this time.'

Kim also revealed she has been suffering with morning sickness during her second pregnancy, and also spoken about her struggles to conceive with Kanye after a difficult delivery with North.

She said: 'It's definitely a different pregnancy. I really wanted to be pregnant, and it's the anticipation of trying.

Getting ready: The pregnant star, who was one of the VIP guests at the MailOnline yacht party in Cannes, said she and her rapper husband read books to North that include stories about being a big sister

Getting ready: The pregnant star, who was one of the VIP guests at the MailOnline yacht party in Cannes, said she and her rapper husband read books to North that include stories about being a big sister

Struggling? Kim revealed she plans to wear 'simple' maternity wear this time round, adding, 'At this stage, I'm just trying to fit into the things that still fit me'
Struggling? Kim revealed she plans to wear 'simple' maternity wear this time round, adding, 'At this stage, I'm just trying to fit into the things that still fit me'

Struggling? Kim revealed she plans to wear 'simple' maternity wear this time round, adding, 'At this stage, I'm just trying to fit into the things that still fit me'

Tough pregnancy: Kim revealed she has been suffering with morning sickness during her second pregnancy

Tough pregnancy: Kim revealed she has been suffering with morning sickness during her second pregnancy

'I feel that this is really a miracle because I didn't think it would happen for me because I had a tough delivery that created some complications.

'So I'm just really grateful to be pregnant, and we're just really happy that so far everything is really healthy, and we're just really excited.'

And she didn't rule out having more children.

'I've always said if I had a boy, I would be done with a boy and a girl.

'But this pregnancy has been a little bit easier, but I won't really know until later on if I can have another one, it depends on my delivery, so hopefully I'll be able to have another one – I wouldn't mind it.' 

At last: Kim spoke about her struggles to conceive with Kanye after a difficult delivery with North

At last: Kim spoke about her struggles to conceive with Kanye after a difficult delivery with North

Looking good: Kim has also revealed she has been suffering with morning sickness during her second pregnancy but that hasn't stopped her maintaining her hectic schedule 

Looking good: Kim has also revealed she has been suffering with morning sickness during her second pregnancy but that hasn't stopped her maintaining her hectic schedule 

Combat king: Kanye was spotted going to a church in Haringey, London, ahead of his Glastonbury performance

Combat king: Kanye was spotted going to a church in Haringey, London, ahead of his Glastonbury performance

Headliner: The rapper will perform on the main stage on Saturday night 

Headliner: The rapper will perform on the main stage on Saturday night 

World Number One: Serena played tennis against students at a park in Bermondsey, London

World Number One: Serena played tennis against students at a park in Bermondsey, London

Figure-hugging: She donned a white Nike top and tight grey leggings 

Figure-hugging: She donned a white Nike top and tight grey leggings 

Victorious: The tennis player celebrated after beating the youngsters at a public park

Victorious: The tennis player celebrated after beating the youngsters at a public park

Bootylicious: Serena flaunted her toned physique in tight leggings and white trainers 

Bootylicious: Serena flaunted her toned physique in tight leggings and white trainers 

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