Ozzy Osbourne was stunned when Sir Paul McCartney refused to collaborate with him - because the former beatle insisted he didn't want to spoil the rocker's record.
The Black Sabbath frontman used a chance meeting with the veteran star to ask whether he would like to make some music together.
And Osbourne was shocked when MCCartney declined, because the Yesterday hitmaker didn't feel he could improve Osbourne's song.
Osbourne tells British magazine Heat, "Meeting Paul MCCartney was f**king phenomenal. I was in the studio at the same time as him, and tried to get him to play bass on one of my songs. But he said he couldn't improve on the bass-line that was there. I said, 'Are you kidding? You could p**s on the record and I'd make it my life."