AceShowbiz - Leona Lewis immediately agreed to sing on Simon Cowell's charity single for Haiti - because watching news coverage of the earthquake-ravaged nation has left her "heartbroken". The music mogul has been busy lining up celebrities to sing a cover of R.E.M.'s "Everybody Hurts" to raise money for the Haiti aid appeal, following a request from Britain's Prime Minister Gordon Brown.

So far, Lewis, Michael Buble and Rod Stewart have all signed up, with Take That, Robbie Williams and Coldplay also rumored to be taking part. And the "Bleeding Love" hitmaker admits she didn't hesitate to offer her help to Cowell, as she's been so saddened by the devastating images from Haiti, which was hit by the massive quake last week, on January 12.

She tells Britain's The Sun newspaper, "You can definitely count me in. What happened in Haiti is absolutely heartbreaking." The members of R.E.M. have also agreed to lend their support to the project, by waiving royalties for the use of the track.

Their manager Bertis Downs says, "We are deeply touched the song has been chosen for this Haiti campaign. It means a lot that the song the guys wrote all those years ago will be used for such an important appeal."