When he was given permission by the Queen to use Windsor Castle for a gala dinner, the Duke of Cambridge compiled a guest list which included Emma Watson, Kate Moss, Cate Blanchett, Margot Robbie, Helena Bonham-Carter and Cara Delevingne.
One woman not in attendance, however, was the Duchess of Cambridge, so it's to be hoped she isn't the jealous type.
Aussie stars grace Prince's party
RAW VISION: Hollywood A-listers, including Margot Robbie and Cate Blanchett, join Prince William for a charity dinner at Windsor Castle for The Royal Marsden cancer centre.
The Duke hosted the event for the Royal Marsden cancer hospital without the Duchess, part of a new strategy by the couple to divide their duties so they can be present at more events.
While the Duchess stayed in with Prince George, the Duke greeted an array of stars, who also included Benedict Cumberbatch, Mario Testino and Laura Carmichael of Downton Abbey.
For the staff of The Royal Marsden, however, there was only one star of the show - the fashion designer Ralph Lauren, who announced he is funding an entire new breast cancer centre at the hospital.
Lauren, 74, and his wife of 50 years, Ricky, made a rare foray away from their home in the US to attend the event and launch the Ralph Lauren Breast Cancer Centre.
Lauren, who had a benign brain tumour removed 25 years ago and lost his close friend Nina Hyde to breast cancer in 1990, has donated millions to cancer research around the world over the past 20 years.
He already donates proceeds from UK sales of his Pink Pony range of clothing and accessories to The Royal Marsden, of which the Duke is President, a position once held by his mother.
Celebrity guests, all friends or supporters of the hospital, wore Ralph Lauren from head to toe.
Cate Blanchett wore an ivory silk evening dress with Ralph Lauren watch and jewellery and diamond chandelier earrings.
Emma Watson wore a silk jersey evening skirt and shirt.
Helena Bonham Carter wore a midnight navy silk taffeta and organza evening dress.
Benedict Cumberbatch wore a Ralph Lauren tuxedo and dress shirt.
In the castle's grand reception room the Duke was introduced to Mr and Mrs Lauren, and immediately apologised for the Duchess's absence.
He said: "I'm sorry my wife's not here, you probably would far rather have seen my wife."
"Not at all," said Mr Lauren.