Adam Levine has a ''dirty mouth''.

The 33-year-old Maroon 5 front man admits he swears too much, and has pledged to make a donation to charity every time he lets rip with a profanity while appearing as a mentor on the US version of 'The Voice'.

He told People Magazine: ''I have a dirty mouth. I curse a lot and I want to try to contain that a little bit.

''I'll have a little curse jar next to me. Every time we say a bad word, $100 (£60) goes to charity. It will help us, it really will. Because we'll end up giving a lot!''

This won't be the first time the kind-hearted 'Moves Like Jagger' hitmaker has given to a good cause - he stripped off last year and posed naked in Cosmopolitan magazine to raise awareness of prostate and testicular cancer.

Discussing the campaign, he said: ''I spend most of my life naked.

''In fact, I often have to be told by the people around me that it's inappropriate to be as naked as I am. But I live in California, where it's always warm, so why not?''