Alice, a 10-year-old cancer patient at The Royal Marsden Hospital in London, snagged a one-on-one with Prince William -- who has followed in his Princess Diana's footsteps by becoming president of the world-renowned cancer hospital.
When the opportunity arose, Alice asked William what he would do if he could be invisible for one day. The Prince replied, "I'd probably get myself in a lot of trouble... I'd probably go in the newspaper office and hide in the background and listen to all the stories they'd talk about me."
"Extra" wants to know -- what would you do if you could be invisible for a day? Post your answers below!