Wills was hosting the event, sponsored by designer
"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,
"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
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
"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."
"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."