Martin said he composed new music for Rihanna's next album but he is not sure whether she has kept it.
"I wasn't necessarily with (Rihanna in the studio), I was working for her. I don't think she even asked, I just said, 'please can I try something?'," Martin said in a radio interview.
"She has so many amazing people writing for her. It's like trying to win 'American Idol', getting a song on Rihanna's album. It's hard. Everybody wants to write songs for her," Martin said.