The proposed collaboration between Amy Winehouse and Pete Doherty has hit a stumbling block after the English jazz singer refused to record a Billie Holiday song. The Rehab singer didn't want to cover a song from the jazz legend, and would prefer to make an original song instead. She says, "Pete wanted to do a Billie Holiday cover and I was like 'No, let's write something together.' "I like writing songs. He's an amazing songwriter and I'd love to be able to say that I wrote a song with Pete Doherty."