Gallery: Prince hosts gala dinner

Prince William, Duke of Cambridge, speaks with Emma Watson at a dinner to celebrate the work of The Royal Marsden at Windsor Castle. Photo: Doug Seeburg/AP

Prince William, Duke of Cambridge, speaks with Emma Watson at a dinner to celebrate the work of The Royal Marsden at Windsor Castle. Photo: Doug Seeburg/AP

Model Jessica Michibata arrives for a dinner to celebrate the work of The Royal Marsden hosted by Britain Prince William at Windsor Castle. Photo: Chris Jackson/Reuters

Ralph Lauren and Ricky Anne Loew-Beer arrive for a dinner to celebrate the work of The Royal Marsden hosted by Britain Prince William at Windsor Castle. Photo: Chris Jackson/Reuters

Actress Zhang Ziyi arrives for a dinner to celebrate the work of The Royal Marsden hosted by Britain Prince William at Windsor Castle. Photo: Chris Jackson/Reuters

Actor Benedict Cumberbatch arrives for a dinner to celebrate the work of The Royal Marsden hosted by Britain Prince William at Windsor Castle. Photo: Chris Jackson/Reuters

Model Kate Moss arrives for a dinner to celebrate the work of The Royal Marsden hosted by Britain Prince William at Windsor Castle. Photo: Chris Jackson/Reuters

Actress Emma Watson arrives for a dinner to celebrate the work of The Royal Marsden hosted by Britain Prince William at Windsor Castle. Photo: Chris Jackson/Reuters

Model Cara Delavigne arrives for a dinner to celebrate the work of The Royal Marsden hosted by Britain Prince William at Windsor Castle. Photo: Chris Jackson/Reuters

Actress Helena Bonham-Carter arrives for a dinner to celebrate the work of The Royal Marsden hosted by Britain Prince William at Windsor Castle. Photo: Chris Jackson/Reuters

Actress Cate Blanchett arrives for a dinner to celebrate the work of The Royal Marsden hosted by Britain Prince William at Windsor Castle. Photo: Chris Jackson/Reuters

The Duke of Cambridge, left, speaks with Benedict Cumberbatch at a dinner to celebrate the work of The Royal Marsden at Windsor Castle. Photo: Doug Seeburg/AP

Prince William, Duke of Cambridge, left, speaks with Ralph Lauren at a dinner to celebrate the work of The Royal Marsden at Windsor Castle. Photo: Doug Seeburg/AP

From left: Paul Arrouet, Dylan Lauren, Ralph Lauren, Ricky Anne Loew-Beer, Andrew Lauren, Lauren Bush and David Lauren pose at a dinner to celebrate the work of The Royal Marsden at Windsor Castle. Photo: Doug Seeburg/AP

Prince William, Duke of Cambridge, left, speaks with Cate Blanchett at a dinner to celebrate the work of The Royal Marsden at Windsor Castle. Photo: Doug Seeburg/AP