Sharon Osbourne, Rupert Grint and Tyra Banks have also raided their closets to support the Give Up Clothes for Good campaign, to raise money for Cancer Research U.K.
Banks has offered up a Catherine Malandrino dress and Osbourne has donated a Burberry coat, while funnyman Walliams has parted with a Tom Ford suit.
He says, "While I would have loved to keep it, I know it will be raising money for an important cause. Cancer is such a horrible disease at any age, let alone when you’re a child, so we need to do everything we can to help fund more research. Please take part in this campaign and help save more lives.”
The sale starts on website eBay.com on Thursday (25Mar10) and will run for one week.