Sheeran has donated T-shirts and hooded sweaters to the online Tags On sale, while Allen, who is also known by her married name Lily Rose Cooper, is selling off designer dresses by Erdem and Marc Jacobs.
The A Team hitmaker is handing over the cash he raises to two charities, including homelessness organisation Crisis U.K. and a children's hospice in England.
Announcing the auction on his Twitter.com page, Sheeran writes, "I'm selling my clothes on Tags On... Get bidding for 2 great causes, Crisis Uk & Bluebell Wood Children's Hospice. These are my clothes I'm selling, it's all for 2 amazing causes. I'll be adding more clothes soon, hoodies and all."
Pop star Eliza Doolittle, U.K. boyband JLS and actress Sadie Frost have also donated clothes and shoes to the Internet auction.