Producer Mark Ronson has quashed reports he'll be laying down vocals on new tunes - insisting his singing voice is best left unheard. The Grammy-winning star can't even summon the courage to add guide vocals to the tracks he writes - because he's too embarrassed to play his performances to the talented singers he collaborates with. He says, "I don't know where that story came from. I'd love to be able to sing, but it's not something I was born with. "I work with so many amazing singers such as Amy Winehouse and I wouldn't have the nerve to play them my demos. It'd be awful."