That's one for the album! Pregnant Kim Kardashian parties with her famous family as she attends designer's glitzy birthday bash

They're long-time friends so she was hardly going to miss his star-studded birthday party despite being heavily pregnant.

And even so, Kim Kardashian favoured style over comfort as she squeezed her baby bump into sheer and skin-tight number as she joined her famous family at Balmain designer Olivier Rousteing's belated celebrations on Friday evening.

Posing up for a series of showbiz snaps on the night, the 34-year-old joined her mother Kris Jenner and her toyboy, Corey Gamble, sister Kourtney and the designer himself for one very lovely picture. 

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Glitzy do: Pregnant Kim Kardashian  celebrated Olivier Rousteing's birthday with (from left to right) Corey Gamble, Kris Jenner, the birthday boy and Kourtney on Friday night in LA

Glitzy do: Pregnant Kim Kardashian celebrated Olivier Rousteing's birthday with (from left to right) Corey Gamble, Kris Jenner, the birthday boy and Kourtney on Friday night in LA

The most showbiz party ever? The group were joined by theSmiths and Mary J Blige at the do

The most showbiz party ever? The group were joined by theSmiths and Mary J Blige at the do

The group mingled with a host of showbiz stars on the night, including supermodel Cara Delevingne, Jada, Jaden and Willow Smith, as well as Kendall Jenner.

Also present was Jessica Biel and Justin Timberlake, Jennifer Lopez and Casper Smart and Kate Hudson.  

Instagram queen Kim, 35, shared a selection of group shots on the photo-sharing app which revealed what guests got up to inside the secret venue - namely, posing and pouting.

See more of the latest Kim Kardashian news, photos and video updates

Cosying up: Supermodel Chanel Iman caught up with the group as they enjoyed refreshments (left) 

Cosying up: Supermodel Chanel Iman caught up with the group as they enjoyed refreshments (left) 

Snap happy: The partygoers put on their best pouts for the cameras

Snap happy: The partygoers put on their best pouts for the cameras

Not quite in nesting mode: Pregnant Kim squeezed her baby bump into a sheer number  with (from left to right) Kendall, Cara Delevingne, Kourtney, Kris and Kylie

Not quite in nesting mode: Pregnant Kim squeezed her baby bump into a sheer number with (from left to right) Kendall, Cara Delevingne, Kourtney, Kris and Kylie

Make a statement with a multi strand necklace like Kourtney

Kourtney Kardashian gave us a lesson in amping up wardrobe basics as she partied on Friday.

The reality TV star gave her simple sweater a luxe edge with a multi chain necklace by Balmain - a snip at $1775. We hope Balmain designer Olivier Rousteing gave her a discount!

If you're looking to update your look for Autumn on the cheap, standout accessories are the answer, and a statement necklace like Kourtney's will put a new season stamp on everything from LBD's to knitwear.

Sadly Kourtney's exact necklace is now sold out (cause we were DEFINITELY going to buy it...) however you can get the look on the high street with our necklace edit below.

Claire's option will look great with a simple T-shirt or plunging dress, or why not stack up a few of Mango's style to cheat Kourtney's designer look?

* PRICES MAY NOT BE AS ADVERTISED

She posed alongside Kourtney, 36, Kendall, 19, Kylie, 18, Kris, 59 and Cara, 23, and the girls gave their best model faces.

Kim was seen placing a protective hand atop her expanding tummy in her skin-tight outfit which also revealed her black bra due to the semi-sheer nature of the fabric. 

The nine-strong selfie spree saw Kim - who is eight months pregnant with her second child - cosy up to her family as well as sibling Jaden, 17, and Willow, 14, and of course the birthday boy himself. 

Three's company: Balmain fans Kim, 35, and Kourtney, 36, gave the camera their best pouts as they cosied up to the birthday boy

Three's company: Balmain fans Kim, 35, and Kourtney, 36, gave the camera their best pouts as they cosied up to the birthday boy

Selfie game on-fleek: Jaden Smith gave the supposed selfie queen a run for her money

Selfie game on-fleek: Jaden Smith gave the supposed selfie queen a run for her money

Family affair: Jaden, 17, was joined by his younger sister 14-year-old Willow Smith who pulled a silly pose alongside a pouting Kim 

Family affair: Jaden, 17, was joined by his younger sister 14-year-old Willow Smith who pulled a silly pose alongside a pouting Kim 

'Crew love': The mother-of-one gushed about her close-knit family, the birthday boy and half-sister Kylie's boyfriend Tyga 

'Crew love': The mother-of-one gushed about her close-knit family, the birthday boy and half-sister Kylie's boyfriend Tyga 

It's all in the genes: Kris posed with daughters Kourtney and Kim

It's all in the genes: Kris posed with daughters Kourtney and Kim

Party princesses: The sisters looked thrilled to be letting their hair down with one another 

Party princesses: The sisters looked thrilled to be letting their hair down with one another 

Eye-popping display: Kim's pert cleavage took centre stage as she squeezed it into a semi-sheer top 

Eye-popping display: Kim's pert cleavage took centre stage as she squeezed it into a semi-sheer top 

All-black everything: The Keeping Up with the Kardashians star stuck to her fail-safe maternity style as she squeezed her curves into an all-black outfit which concealed her growing baby bump but revealed her sizable breasts
All-black everything: The Keeping Up with the Kardashians star stuck to her fail-safe maternity style as she squeezed her curves into an all-black outfit which concealed her growing baby bump but revealed her sizable breasts

All-black everything: The Keeping Up with the Kardashians star stuck to her fail-safe maternity style as she squeezed her curves into an all-black outfit which concealed her growing baby bump but revealed her sizable breasts

Individual senses of style: While Kim, 35, favoured a skin-tight outfit, Kourtney, 36, looked suitably smart in two-tone separates

Individual senses of style: While Kim, 35, favoured a skin-tight outfit, Kourtney, 36, looked suitably smart in two-tone separates

Smart separates: The mother-of-three chose to conceal her svelte figure and was the vision of class

Smart separates: The mother-of-three chose to conceal her svelte figure and was the vision of class

Balmain birthday boy: The famous sisters - who are both close with designer Olivier - ensured they had a momento to keep from the special occasion

Balmain birthday boy: The famous sisters - who are both close with designer Olivier - ensured they had a momento to keep from the special occasion

Pouting party-go-ers: The trio gave the camera their best model poses

Pouting party-go-ers: The trio gave the camera their best model poses

'Birthday Boy!!!! Love celebrating with you!! @olivier_rousteing,' she captioned a shot of herself and Kourtney with Olivier.

While series of Emojis served to summarise her feelings in most of the shots, she reserved some sweet words for a picture which showed Kris, Kourtney, Olivier, Kylie and her boyfriend Tyga.

'Crew love #BalmainArmy #HappyBirthdayOlivier,' she simply captioned it.

'Squad': The guestlist struck confident poses as they lapped up the celebrations

'Squad': The guestlist struck confident poses as they lapped up the celebrations

Keeping his hands on his woman: The music manager placed a protective hand on the Kardashian matriarch's waist

Keeping his hands on his woman: The music manager placed a protective hand on the Kardashian matriarch's waist

All the love: Olivier planted a soft kiss on Jada's cheek in this sweet group shot

All the love: Olivier planted a soft kiss on Jada's cheek in this sweet group shot

Playing the selfie queen at her own game: Jaden Smith, 17, volunteered himself to snap a selfie of him, Kourtney, Kim and his sister Willow, 14

Playing the selfie queen at her own game: Jaden Smith, 17, volunteered himself to snap a selfie of him, Kourtney, Kim and his sister Willow, 14

Trust her: While you'd think it was Olivier's time to shine, a provocatively-dressed Kylie, 18, stole his spotlight as she turned up in a show-stopping number designed by the birthday boy himself
Trust her: While you'd think it was Olivier's time to shine, a provocatively-dressed Kylie, 18, stole his spotlight as she turned up in a show-stopping number designed by the birthday boy himself

Trust her: While you'd think it was Olivier's time to shine, a provocatively-dressed Kylie, 18, stole his spotlight as she turned up in a show-stopping number designed by the birthday boy himself

Hair she goes: Kylie showed off newly-short sleek raven bob as she struck a pose on the grass in her towering stilettos which were starting to sink into the ground

Hair she goes: Kylie showed off newly-short sleek raven bob as she struck a pose on the grass in her towering stilettos which were starting to sink into the ground

Alright for some: The crocheted dress perfectly flattered her figure and was a gift from close family friend Olivier

Alright for some: The crocheted dress perfectly flattered her figure and was a gift from close family friend Olivier

Here they are: Kylie and Tyga looked every inch the power couple as they posed for pictures throughout the night dressed in colour co-ordinating ensembles

Here they are: Kylie and Tyga looked every inch the power couple as they posed for pictures throughout the night dressed in colour co-ordinating ensembles

Do your thing: Tyga was more than happy to take pictures of his lovely lady with Olivier

Do your thing: Tyga was more than happy to take pictures of his lovely lady with Olivier

Three's not a crowd: The couple caught up with the birthday boy who too put on a suave display in a simply stylish all-black outfit

Three's not a crowd: The couple caught up with the birthday boy who too put on a suave display in a simply stylish all-black outfit

'Thank you for this beautiful dress': Dressed in a white-net Balmain creation, Kylie cuddled up to the desinger

'Thank you for this beautiful dress': Dressed in a white-net Balmain creation, Kylie cuddled up to the desinger

Whoosh: She jumped on a swing with sister Kendall (who was wearing the same shoes but in a different colour) and supermodel Cara, 23

Whoosh: She jumped on a swing with sister Kendall (who was wearing the same shoes but in a different colour) and supermodel Cara, 23

Swingers: Kendall, Cara and Kylie piled onto a make-shift swing

Swingers: Kendall, Cara and Kylie piled onto a make-shift swing

City girl: The KUWTK star gazed towards the picturesque view while showing off her narrow waist and generous behind

City girl: The KUWTK star gazed towards the picturesque view while showing off her narrow waist and generous behind

Ooh er: The 18-year-old took to Snapchat to share a different and more racy perspective of the revealing dress

Ooh er: The 18-year-old took to Snapchat to share a different and more racy perspective of the revealing dress

While you'd think it was Olivier's time to shine, a provocatively-dressed Kylie stole his spotlight.

The youngest member of the Kardashian-Jenner clan ended up being a magnet of attention herself when she arrived to his belated birthday party in a revealing white dress, designed by Olivier himself, that hugged every inch of her hour-glass frame.

The 18-year-old Instagrammed a photo of herself cuddling up to the Balmain creative director in the skin-tight white net garment, which she captioned: 'I love you @olivier_rousteing thank you for this beautiful dress.' 

Olivier's 29th birthday actually fell as he prepared for his star-studded Paris Fashion Week show last month, hence his decision to celebrate belatedly.

The supermodel way: Kendall, 19, proved less is more as she slipped into nude military-style separates
The supermodel way: Kendall, 19, proved less is more as she slipped into nude military-style separates

The supermodel way: Kendall, 19, proved less is more as she slipped into nude military-style separates

Good choice: The neutral colour complemented the catwalk queen's skin tone while the cinched eyelet top accentuated her lithe figure

Good choice: The neutral colour complemented the catwalk queen's skin tone while the cinched eyelet top accentuated her lithe figure

Watch your step: She and model mate Cara, 23, looked a little unsteady as they trotted across the grass in their towering stilettos

Watch your step: She and model mate Cara, 23, looked a little unsteady as they trotted across the grass in their towering stilettos

'Balmain Babies':  Kim and Kourtney pouted in the back of their car en route to the birthday bash

'Balmain Babies':  Kim and Kourtney pouted in the back of their car en route to the birthday bash

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