Prince William hosts Emma Watson, Cate Blanchett at Windsor Castle

Prince William, Duke of Cambridge, flew solo Tuesday night for a charity dinner at Windsor Castle -- but despite his wife’s absence, there was no lack of glamour surrounding the royal.

Wills was hosting the event, sponsored by designer Ralph Lauren, to benefit the Royal Marsden cancer hospital, one of Princess Diana’s favorite charities. The second-in-line to the British throne has served as the hospital’s president since 2007.

“I am enormously grateful to Ralph Lauren for his generosity, and to all of you who so kindly support the hospital,” William said in his speech. “You should know that what you do saves lives and gives hope to thousands of people.”

Later, the duke said (via Us Weekly) it was “a wonderful thing” that Lauren was backing the “great addition to the hospital.” However, he did apologize for his fashionable wife’s absence -- Catherine was busy tending to their son, Prince George.

“I’m sorry my wife’s not here,” he said (via People) when he introduced the designer in the castle’s Grand Reception Room. “You probably would far rather [see] my wife.”

Lauren, who attended the event with wife Ricky Anne Loew-Beer, dressed several of the celebrities for the event, including “Harry Potter” star Emma Watson and Oscar winner Cate Blanchett.

After the reception, the 230-person party moved to the castle’s ornate St. George’s Hall for a lavish three-course dinner set across two long tables, the Daily Mail reported.

“The King’s Speech” actress Helena Bonham Carter also showed her support and said that these events were crucial to raising awareness and funds to fight cancer.

“It requires a huge amount of money to come up with a cure for cancer,” she said. “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.”

Carter also noted that she had met the duke in the past when she was vacationing in the Caribbean.

“The duke and I met before, along with the Duchess, before they were married, when I was staying on Mustique,” the actress said. “I got very drunk at one point and I was determined to ask him to be a godfather to my daughter. He quite wisely said no.”

The actress, who has long been linked to director Tim Burton, said that she admired the prince and that “he has got the same grace as both his parents.”

When model Kate Moss, the queen of the catwalk, met the prince, she also asked about his wife’s whereabouts -- rather flirtatiously, according to the Daily Mail. When he said Catherine wasn’t there, Moss replied, “Such a shame.”

“Sherlock” star Benedict Cumberbatch said that he felt “guilty” that he chatted with the prince for so long.

“He is just a stand-up guy,” said the “Hobbit” actor. “I completely forgot to ask him how he got over his jet lag from his trip to Australia, because I was there at the same time and I saw all the commotion when he went to Sydney Opera House.”

The duke and duchess wrapped up their highly publicized three-week tour of New Zealand and Australia last month.

Cumberbatch added that he hoped the evening would get the Royal Marsden on people’s radar.

“That’s what we’re here for,” he said. “Cancer isn’t a disease that needs much awareness, but it does need continued funding for research.”

Also in attendance were Victoria’s Secret model Cara Delevingne, “Downton Abbey’s” Laura Carmichael, Allen Leech and Lily James, “Game of Thrones” star Sophie Turner, “The Wolf of Wall Street’s” Margot Robbie and photographer Mario Testino, among many others.