Prince William hosted a dinner tonight at Windsor Castle to honor the work of The Royal Marsden cancer center. The glittering gala had an impressive guest list: with stars such as Cate Blanchett, Kate Moss and Emma Watson in attendance. One very fashionable lady was missing, however, his wife Kate! The Duchess was reportedly home with baby George as the Duke and Duchess attempt to divide their appearances to keep the focus on the cause at hand.

The Duke, following in his mother's footsteps when he became president of the Royal Marsden in 2007, hosted the dinner at the stunning Windsor Castle. Also being honored this evening was designer Ralph Lauren for his contributions to cancer research(and this particular charity) through the years.

Mr. Lauren announced tonight that he has been working with the Royal Marsden to open the Ralph Lauren Breast Cancer Centre. And very fittingly, many of the stars were dressed in the American designer's pieces from head to toe.

When William was introduced to Mr. Lauren and his wife Ricky, he immediately said to them "I'm sorry my wife's not here, you probably would far rather you saw my wife." "Not at all," Mr. Lauren replied. William then spoke with many of the 200 attendees. Benedict Cumberbatch said he felt "guilty" for taking so much of the Prince's time, but that he's just "such a stand-up guy."

The Duke of Cambridge and Benedict Cumberbatch celebrate the Royal Marsden
Prince William spoke about the importance of the charity and its work, as well as what Ralph Lauren has done. "I am enormously grateful to Ralph Lauren for his generosity, and to all of you who so kindly support the hospital. You should know that what you do saves lives and gives hope to thousands of people."

According to the Daily Mail, "The Royal Marsden is the oldest, largest and most comprehensive cancer centre in Europe, with a history of ground-breaking research." Learn more at royalmarsden.org.

Click through the gallery above to see more photos from the star-studded event!