The flame-haired star was joined by husband Sacha Baron Cohen at the lavish party on Saturday night (25Mar17), but Isla proved her beau isn't the only person that can make people laugh.

Taking to Instagram to share a photo of herself dressed to the nines in a gold and white Zimmermann ruffle dress, Isla joked: "Next time I will try and pluck my knickers out from my tush BEFORE the paparazzi turn up #aboutlastnight."

Fans didn't seem to mind though, with one even cheekily commenting, "Assumed you'd have someone to do that for you these days, @islafisher."

Comedian Sacha kept his look more relaxed, wearing a leather bomber jacket and black baseball cap to the party at the Hammer Museum in Los Angeles.

Elton and husband David Furnish went for more opulent wardrobe choices, with birthday boy Elton donning a maroon suit jacket, burgundy shirt, velvet slippers and red tinted glasses. Meanwhile, David chose an embellished black and gold overcoat.

"Let's get this party started! #SuitedandBooted #HappyBirthdayElton," David shared on Instagram ahead of the party.

The A-list guest list also included Katy Perry, who sparkled in black sequins, Sharon and Kelly Osbourne, who both went for all black ensembles, and James Corden and his wife Julia Carey.

Lady Gaga and Stevie Wonder provided the evening's entertainment, while Britain's Prince Harry made an appearance via video message.

As well as enjoying celebrations, Elton and his famous friends also raised cash for the Hammer Museum and Elton's AIDS Foundation.