Kate Moss, Cara Delevingne, Emma Watson, Benedict Cumberbatch and stars from Downton Abbey have rubbed shoulders with royalty at a bash at Windsor Castle.
Prince William hosted the night, celebrating one of the world's leading cancer-specialist hospitals, the Royal Marsden.
Supermodels Kate and Cara were at the black-tie do with designer Ralph Lauren, who has made a large donation to help fund a new breast cancer research centre which has been named in his honour.
The fashion guru also dressed many of the stars attending the dinner, where the evening's entertainment was provided by singer-songwriter Emeli Sande.
Downton Abbey stars Laura Carmichael and Allen Leech and Hollywood stars Cate Blanchett and Helena Bonham Carter were also at the event.
Helena said: "It requires a huge amount of money to come up with a cure for cancer.
"We now live in times when it doesn't mean death, a lot of people are living with the disease. It's very different from when I was a child, the C word was taboo. Hopefully, for my children, it will be a thing of the past."
Sherlock star Benedict described how he had an affinity with the Duke, with the two men being similar ages, and described him as a "stand up" guy.
He added after speaking to William: "I'm here tonight to show my support, I've done work for various cancer trusts and charities but for the Marsden, it's the first thing I've done for them.
"I've sadly known a lot of people who have been through their doors but the other extent they've been incredibly well treated."
The Royal Marsden was founded as the Free Cancer Hospital in 1851 by Dr William Marsden, and was the first hospital in the world dedicated to cancer treatment and research into the causes of cancer.
The Duke became the hospital's president in 2007, following in the footsteps of his mother Diana, Princess of Wales, who held the same position from 1989 until her death in 1997.