Unfortunately for Princess Beatrice, it wasn't the frock that turned heads.
Arriving for a party, she stepped out of her car and her bodice slipped down – revealing rather more decolletage than royal protocol might allow.
Incoming: Beatrice was very nearly let down by her dress
Bea-have: A bleary-eyed Princess Beatrice enjoyed another night out on the tiles this week at Swarovski's Fashion Rocks eventThe 19-year-old princess's accidental slip happened after the Fashion Rocks extravaganza at the Royal Albert Hall on Thursday night.
Having left the fashion and rock show, held in aid of the Prince's Trust, she repaired to the after-party at the nearby Baglioni Hotel.
Beatrice, who had shared a box with Dame Shirley Bassey and designers for Marchesa earlier in the evening, was ushered into the venue by her hosts and a bodyguard who tried to ensure that nobody stood on her trailing pale green gown.
Wobbles: Princess Beatrice makes her exit from the Prince's Trust event looking somewhat unsteady on her feetShe appeared rather nervous on arrival but soon relaxed with a drink in her hand.
She chatted to Kelly Osbourne, who was in a gothic-style black dress, about the pitfalls of her delicate outfit.
Alluding to her earlier difficulties, Beatrice remarked: "I love it but I keep on having to lift it off the floor and pull the bodice up."
Swig: Chanel model for the night Lily Allen reverted to type after her Fashion Rocks gig with an unladylike swig from a bottle of alcoholWhen the party stared to fill out, Beatrice was whisked into a cordonedoff area where billionaire Topshop boss Philip Green was holding court.
Despite most of her party leaving shortly after midnight, Beatrice stayed beyond 1am to mingle with young guests such as Oscar Humphries, whose father Barry performed at Fashion Rocks.
Mr Green, who had entertained Kate Moss and her boyfriend Jamie Hince in a private box at the show earlier, came to the party without the supermodel but brought along her best friend Davinia Taylor.
Miss Moss stayed away, perhaps having learned that her former boyfriend Pete Doherty had turned up hoping to bump into her there.
She's no lady: Lily was the picture of elegance earlier in the evening - but it didn't take her long to revert to her usual unladylike behaviourShe instead opted for drinks at the Mandarin Oriental Hotel with singer Beth Ditto before going on to the nightclub Paper. She left the club bleary-eyed in the early hours.
Meanwhile at the star-studded event a host of other celebrities partied hard.
Loudmouth Lily Allen had looked demure earlier in Chanel when on the red carpet, but the ladylike veneer soon vanished after a few hours at the after-party.
A worse for wear Lily was seen swigging from a bottle of Jagermeister, a German bitter liqueur, as she left the official Fashion Rocks afterparty at the Baglioni hotel in Kensington at 2am.
Flash: Peaches was ambushed by a surprise flasher
She travelled all of a couple of miles to Punk in Soho, where she carried on partying.
Hardly befitting behaviour for someone wearing Chanel couture - even if it is borrowed. One wonders what Karl Lagerfeld would think?
Earlier the singer, who is dating Chemical Brothers star Ed Simons, was asked the secret to her new slim figure, she answered: "Love".
Titter: The flasher gives Peaches and pal Jamie Winstone something to laugh aboutLily has recently bought a new place in Queen's Park, and has invited Simons to move in with her.
At least she decided to leave the photographers alone on this occasion. The singer received a police caution this week for an alleged attack on a photographer earlier this year.
But for Peaches Geldof, it was less Fashion Rocks and more fashion shocks as she was accosted by a flasher.
As she left Punk Club, a man dressed only in a bathrobe, with the words "the more assured" and a pair of trainers exposed himself to Peaches and her actress friend Jamie Winstone.
After taking a peek, the wannabe DJ, made a fast exit in the back of a black cab with pals.
