From Sir Elton John and Benedict Cumberbatch to Joanna Lumley and Annie Lennox, the world’s biggest celebrities are auctioning off their hats to raise money for a homeless charity.

Hammersmith-based St Mungo’s is calling on hat lovers all over the country to show their support for homeless people by taking part in Woolly Hat Day this Friday (January 31).

Now in its fourth year, hundreds of people will don beanies, berets and baseball caps to help the charity raise money to support homeless men and women.

For one lucky bidder, they could also be wearing a signed Sherlock Deerstalker courtesy of Mr Holmes (or Benedict Cumberbatch) himself.

Joanna Lumley is auctioning her hat to raise money for St Mungo's
 

Fans and supporters of the charity are already bidding on an eBay auction which boasts hats from 30 big names in the music, TV and film industry,

Martin Freeman, who plays Sherlock’s faithful sidekick, Dr Watson, in the latest BBC series, is a big supporter of 2014’s Woolly Hat Day. He said: “Homelessness should be completely unacceptable in the UK. Show your support for St Mungo’s Woolly Hat Day by putting your hat on and raising money for the charity’s work rebuilding lives. By putting your hat on, you’ll be helping homeless people get ahead.”

This hat worn by Chris Martin can be bid on
 

The charity has a new fundraising target of £50,000 from the day alone and with bids on Sherlock’s hat already at £1,120 on Monday afternoon, a good effort is being made towards that.

Tanya English, executive director of fundraising for St Mungo’s said the charity believes everyone should have a right to shelter, and Woolly Hat Day is a chance to show support for those without a home.

“We work all year round to support people to rebuild their lives through good quality housing, health services and opportunities for training and support into work,” she added.

“We want this year to be even more of a success in raising funds and awareness. By putting your hat on for Woolly Hat Day you can help homeless people get ahead.”

Staff at St Mungo's wear orange hats for Woolly Hat Day

To help raise money for Woolly Hat Day, there are a number of ways people can get involved:

  • Bidding in the online celebrity hat auction on eBay which ends at 6pm on Sunday (February 2)
  • Getting friends and teachers together to fundraise
  • Holding a hat party at work
  • Knitting bobble hats with friends or colleagues
  • Make an online or text donation by texting WOOL14 followed by the amount you would like (e.g. £10) to donate to 70070
  • Follow St Mungo’s on Facebook or Twitter .