It's no secret that Taylor Swift, 22, writes about her feelings, including lost loves, and that's exactly what has John Mayer, 34, so upset. Mayer claims that Swift's recent song, "Dear John," from her new album, Speak Now, is about him and their brief romance in 2010.

"It made me feel terrible," Mayer told Rolling Stone about "Dear John" by Swift. "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."

Swift, who never confirmed nor denied the subject of "Dear John," penned the following lyrics in the song: "Dear John, I see it all now, it was wrong / Don't you think 19 is too young to be played with? / The girl in the dress wrote you a song / You should've known."

Mayer, who recently denied that his "Shadow Days" was a farewell song to his ex-love, Jennifer Aniston, now reveals that he thinks such homages constitute "cheap songwriting." About Swift, Mayer said, "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 'til he gets a load of this!' That's bull—t."

Since Mayer and Swift's split, they have also respectively been romantically linked to Jessica Simpson, and Jake Gyllenhall.

Mayer's new album, Born and Raised, debuted as number one in the nation last week.

For more on John Mayer and Taylor Swift:

John Mayer Dismisses Idea That Jennifer Aniston Inspired 'Shadow Days'

VIDEO: Is John Mayer's New Song 'Shadow Days' About Ex Jennifer Aniston?

VIDEO: John Mayer Apologizes For Interview

Jennifer Aniston And John Mayer Split

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VIDEO: Zac Efron And Taylor Swift Duet On 'Ellen'