Aisle be there for you! Paris Hilton supports sister Nicky at her pre-wedding bash in London... but can't resist turning heads in leg-flashing gown

She swore she would wear whatever her younger sister desired for her big day on Friday.

But Paris Hilton stuck to her own head-turning signature style for her sibling Nicky's pre-wedding bash in London on Thursday evening.

The younger of the two Hilton girls kicked off the celebrations ahead of her nuptials with fiance James Rothschild in St. James's, with a host of billionaires and the world's wealthy elite flocking to mark the joining of two of the richest dynasties.

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Showstopping bridesmaid: Paris Hilton ensured she wasn't overlooked as she arrived in St. James's in a racy black evening gown for her sister Nicky's pre-wedding party on Thursday evening 

Showstopping bridesmaid: Paris Hilton ensured she wasn't overlooked as she arrived in St. James's in a racy black evening gown for her sister Nicky's pre-wedding party on Thursday evening 

Despite being on hand to support Nicky, Paris, 34, couldn't resist putting on a show as she arrived at the event.

Dressed to impress in a black sequinned gown, the reality show regular showed off her tanned legs thanks to the dress' daring thigh-high split. 

She lapped up attention outside Spencer House, where the bash was held, posing for photographers as a cascade of super-cars pulled up to drop of the well-heeled revellers.

Speaking about what she would wear for bridesmaid duties, Paris previously said: 'It's her day so whatever she wants me to wear, I will.

'But I know that Nicky has impeccable taste so the bridesmaid dresses are going to be beautiful.' 

Best foot forward: The reality TV regular showed off her legs in the sequinned number, split to the thigh

Best foot forward: The reality TV regular showed off her legs in the sequinned number, split to the thigh

Walk the walk: The 34-year-old will follow her sibling down the aisle at The Orangery in the grounds of the palace

Walk the walk: The 34-year-old will follow her sibling down the aisle at The Orangery in the grounds of the palace

It's my (sister's) party: Paris previously insisted she would wear whatever Nicky insisted for her bridesmaid duties, but stuck to her own signature style for the pre-wedding celebrations

Love is in the air: Paris also showed off her new man at the event as she cosied up to boyfriend Thomas Gross

Love is in the air: Paris also showed off her new man at the event as she cosied up to boyfriend Thomas Gross

Meanwhile, the 31-year-old bride-to-be looked sensational as she arrived at Spencer House in St James on the arm of her handsome beau, a member of the extremely wealthy Rothschild banking family.

Taking inspiration from her upcoming big day, Nicky showed off her legs in an exquisitely detailed cream lace mini-dress, which featured long sleeves and a high neck. 

The couple posed on the steps as they made their way into the event, kick-starting a weekend of extravagant partying.

The countdown begins: Nicky Hilton and her fiance James Rothschild arrive for the pre-wedding party in St. James's on Thursday evening

The countdown begins: Paris' sister Nicky Hilton and her fiance James Rothschild looked loved-up as they arrived for their pre-wedding party in St. James's on Thursday evening

Bride chic: The 31-year-old took inspiration from her big day by wearing a stunning cream lace mini-dress as she posed alongside her husband-to-be

Bride chic: The 31-year-old took inspiration from her big day by wearing a stunning cream lace mini-dress as she posed alongside her husband-to-be

Handsome couple: James, 30, a member of one of world's richest dynasties, looked dapper in a navy suit as he posed for pictures alongside his socialite fiancee

Handsome couple: James, 30, a member of one of world's richest dynasties, looked dapper in a navy suit as he posed for pictures alongside his socialite fiancee

Next walk - the aisle: The pair will wed in an extravagant ceremony at Kensington Palace on Friday

Next walk - the aisle: The pair will wed in an extravagant ceremony at Kensington Palace on Friday

Practice makes perfect: Nicky carefully navigated her steps as she strutted in pointed nude stilettos 

Practice makes perfect: Nicky carefully navigated her steps as she strutted in pointed nude stilettos 

Family function: Nicky's parents Richard and Kathy beamed as they stood at the entrance of the venue

Family function: Nicky's parents Richard and Kathy beamed as they stood at the entrance of the venue

Other connected guests included Formula One billionaire Bernie Ecclestone's glamorous daughter Petra Stunt, who was on the arm of her businessman husband James.

Singer Holly Valance also arrived in a short black dress, and put on a busty display thanks to the frock's keyhole design. 

She was joined by her own billionaire beau, property developer Nick Candy.

It may have been packed with the world's wealthy elite, but the party wasn't missing a political heavy weight or two.

Chelsea Clinton, daughter of former US president Bill and future White House hopeful Hillary, also arrived alongside her husband Marc Mezvinsky.

Guest of honour: Naomi glittered in a metallic mini dress as she also made an appearance at the party

Guest of honour: Naomi glittered in a metallic mini dress as she also made an appearance at the party

Good neighbour: Holly Valance put on a bust display as she sported a LBD with a keyhole feature for the well-heeled bash

Good neighbour: Holly Valance put on a bust display as she sported a LBD with a keyhole feature for the well-heeled bash

Billionaire's club: The former soap star was joined by her property developer husband Nick Candy

Billionaire's club: The former soap star was joined by her property developer husband Nick Candy

The thigh's the limit: Another wealthy reveller was Petra Stunt, who showed off her legs in a split black skirt matched with a pearl-embroidered top

The thigh's the limit: Another wealthy reveller was Petra Stunt, who showed off her legs in a split black skirt matched with a pearl-embroidered top

Social scene: The Formula One heiress was accompanied by her own billionaire beau, businessman James Stunt

Social scene: The Formula One heiress was accompanied by her own billionaire beau, businessman James Stunt

Political heavyweight: Chelsea Clinton, daughter of former US president Bill and future White House hopeful Hillary, also arrived alongside her husband Marc Mezvinsky

Political heavyweight: Chelsea Clinton, daughter of former US president Bill and future White House hopeful Hillary, also arrived alongside her husband Marc Mezvinsky

Nicky and James have been dating since 2011, and the wealthy Brit proposed last August while visiting Italy's Lake Como. 

Speaking about her desire to lay on her nuptials away from her native US, Nicky explained: 'I’ve always wanted a destination wedding and I love London, so I’m leaning towards London.'

They will exchange vows in The Orangery at the palace, close to the London residence of Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge. 

This will actually mark the second wedding for Nicky, who married childhood friend Todd Andrew Meister in Las Vegas 10 years ago, only for the marriage to be annulled three months later. 

Stylish guests: Ben Goldsmith  looked very happy as he posed with his wife Jemima  (R) and Mary-Clare Elliot

Stylish guests: Ben Goldsmith  looked very happy as he posed with his wife Jemima (R) and Mary-Clare Elliot

Royal connection: Princess Beatrice's boyfriend Dave Clark (right), who works for Richard Branson, also attended with two pals

Royal connection: Princess Beatrice's boyfriend Dave Clark (right), who works for Richard Branson, also attended with two pals

Arriving in style: A fleet of luxury cars were seen pulling up to the venue as guests arrived for the party

Arriving in style: A fleet of luxury cars were seen pulling up to the venue as guests arrived for the party

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