Coldplay are encouraging fans to raise money for Crisis - in return for hard-to-get tickets for their exclusive Hidden gig.
The top 12 fundraisers will win tickets to see the Grammy award-winning band perform at two sold-out secret venues, the first in Liverpool on December 19 and in Newcastle on December 20.
"We're doing the Crisis gigs because we think that what they do is cool - it's not about the weight of our influence or anything like that; it's just what we can give," said frontman Chris Martin.
"It was around 12 years ago that I started getting to know more about what they do. I think they're an amazing organisation."
He added: "I didn't know much about homelessness beforehand. I thought it was to do with people sleeping in shop doorways. As you learn more you realise that it goes far beyond that."
From December 3 to December 13, fans have a chance to get a pair of the in demand tickets by raising as much money as they can for the homeless charity, by registering at www.nokia.co.uk/hiddengigs.