Chris Martin the plumber

Chris Martin has become a plumber at a homeless shelter.

The Coldplay frontman - who is well-known for his charity work - has been using his skills to help out at a temporary shelter for alcoholics in London.

A source at the shelter, run by the Crisis charity, told Britain's Daily Express newspaper: "Chris has been doing their plumbing for them. He does this every year, for free. Apparently he's quite a dab hand with it all." Chris - who is married to Hollywood beauty Gwyneth Paltrow - is keen to remain anonymous.

A Crisis spokesperson said: "We have 7,000 volunteers helping at Christmas.

There are celebrities among them but we can't name those who wish to remain anonymous."

It was recently revealed Coldplay's new album has turned Chris into an insomniac.

Chris is determined to make the British band's fourth studio album - which is due to be released next February and expected to be called 'Prospekt' - as successful as their hit 2005 LP 'X+Y' and has been working round the clock on new material.

An unknown source named Prospekt wrote on the band's official website:

"Chris just keeps on writing. He has shown me five new songs in the last two days. I seriously don't know when he sleeps."