London: Singer Chris Martin says he was scared to ask Rihanna to appear as a guest-vocalist for his rock band Coldplay`s new album "Mylo Xyloto".
"The album is designed as a whole piece. It has boy and girl lead characters and top of our list for the girl part was Rihanna. But it took a while to pluck up the courage to ask her," contactmusic.com quoted Martin as saying.
"She has such an amazing voice and it`s so different to mine. When the vocal happened I thought `Wow, you sound different` but I think that`s also because she was singing a different song to what we are used to hearing from her and it is written by a guy from Devon," he added.
`Mylo Xyloto` will be released Oct 24 this year.