The Charities Aid Foundation has teamed up with eBay for Charity to run a high-profile online celebrity fundraising auction during its National Giving Week in October.
CAF, which organises the annual fundraising drive, has appealed to celebrities to donate unique items that will be auctioned to raise funds for the charity of their choice.
The auction will be promoted to the 10 million registered users of eBay in the UK.
Celebrities that have already contributed include actors Kate Winslet and Ewan McGregor, former Beatle Ringo Starr and the broadcaster Dermot O'Leary.
"The theme of this year's National Giving Week is 'Give It Up For'," said Sachaa Pattison, marketing and communications manager at CAF. "Celebrities will be asked to give something up to support their favourite causes."
In a separate National Giving Week event, the 12,000 charities registered with eBay for Charity will be challenged to see which of them can raise the most money from the auction of items donated by supporters throughout October.
National Giving Week will this year run from 16 to 22 October.