John Mayer was "humiliated" by Taylor Swift's song about him.

The guitarist was reportedly the inspiration behind his former lover's track "Dear John'" - which came out a few months after he was slammed for branding ex-girlfriend Jessica Simpson "sexual napalm" - but he is upset about the record, saying it was a "lousy" thing to write.

"I was really caught off-guard, and it really humiliated me at a time when I'd already been dressed down. I mean, how would you feel if, at the lowest you've ever been, someone kicked you even lower? It made me feel terrible. Because I didn't deserve it. I'm pretty good at taking accountability now, and I never did anything to deserve that. It was a really lousy thing for her to do," he told Rolling Stone.

The song was included on Taylor's multi-million selling Speak Now album, and features cutting lyrics, including, "Dear John, I see it all, now it was wrong / Don't you think 19 is too young / to be played by your dark twisted games, when I loved you so?"

John had a brief relationship with Taylor before Speak Now came out, and shortly afterwards he took two years away from music to deal with some vocal problems.

The 34-year-old musician - who has also dated other beauties including Cameron Diaz and Jennifer Aniston - also took aim at Taylor for writing the song and it being so obviously about their relationship: "I will say as a songwriter that I think it's kind of cheap songwriting. I know she's the biggest thing in the world, and I'm not trying to sink anybody's ship, but I think it's abusing your talent to rub your hands together and go, 'Wait till he gets a load of this!' That's bull****t."