Coldplay frontman Chris Martin says he wants to write songs for pop star Rihanna, but adds that it's not easy to get a chance to be part of her soundtrack.

Martin personally approached the `Rude Boy` hitmaker to ask if he can submit some tracks for her next album, reports contactmusic.com.

Martin said: "I don't even think she asked. I just said, 'Please can I try something?"

Despite his impressive back catalogue, the singer-songwriter, who previously collaborated with Rihanna on the Coldplay track `Princess of China`, is still worried his songs won't make the final cut.

"She has so many amazing people writing for her. It's like trying to win 'American Idol', getting a song on Rihanna's album,` he said.