This year over 30 celebrities, including two-time BAFTA winner Ed Sheeran, Oscar-nominated Eddie Redmayne and Dame Vivienne Westwood, are joining forces with charity St Mungo's Broadway to show their support for homeless people.
Running for it's fifth year Woolly Hat Day, which will take place on 30 January, sees thousands of people all over the country wearing a range of headwear to help raise money for its work supporting homeless men and women.
The Celebrity Hat ebay auction, which will run from 23 January to 1 February 2015, features donations of fabulous hats from a fantastic range of celebrities.
The charity's Chief Executive Howard Sinclair explained; "St Mungo's Broadway believes that no one should be homeless. Woolly Hat Day is your chance to show support for those without a home, or at risk of losing one.
There’s no running, hiking, swimming, trekking or jumping out of aircraft involved – we simply invite you to wear a hat and get involved to help us raise awareness and funds" he added.
This year the charity is aiming to raise £60,000 during Woolly Hat Day, which would make life-changing differences to vulnerable people affected by homelessness.