Coldplay frontman Chris Martin gets embarrassed when he thinks about his band's duet with Richard Ashcroft at the London leg of Live 8, because they played like "c**p".

Coldplay teamed up with Ashcroft at the 2 July (05) charity event to sing The Verve hit Bittersweet Symphony, but Martin wishes they'd rehearsed a little more beforehand.

He says, "Richard Ashcroft was brilliant but I thought we were c**p.

"Robbie Williams was absolutely amazing, so were Pink Floyd."