The Why Does It Always Rain On Me? singer was inspired to give up eating animal products by his Beatles hero's strict meat-free diet, but he has eventually weakened and now happily consumes fish.
Healy worked with MCCartney on his 2010 solo album Wreckorder and they became good pals, but now he is terrified the Hey Jude hitmaker will find out his guilty secret.
Letting slip his dietary lapse in an interview for British magazine Radar, Healy says, "I eat fish now. But I'll kill you if you put that in the article because he'll come after me. I'm not very organised with my diet so when I was a total veggie about three years ago I didn't think I was getting the right things, so fish helps."