John Mayer. (Ethan Miller/Getty Images)

In an interview with Rolling Stone, Mayer said that Taylor Swift’s song “Dear John” made him “feel terrible.”

“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.”

Mayer worked with Swift on his song “Half of My Heart” in 2009, around the time the two were rumored to be dating around. It is believed that Mayer ended the fling.

On her 2010 album “Speak Now,” Swift released “Dear John,” a ballad long believed to be about the singer’s brief dalliance with Mayer thanks to its title and extremely literal lyrics: “Dear John/I see it all now that you’re gone/Don’t you think I was too young/To be messed with/The girl in the dress/Cried the whole way home/I should’ve known.”

Mayer declined to talk about the “too young to be messed with” lyric in the song, but he did tell Rolling Stone he thought “Dear John” is “cheap songwriting.”

“I think it’s abusing your talent to rub your hands together and go, ‘Wait till he gets a load of this!’ That’s [expletive],” Mayer said.

Swift fans on Twitter responded to Mayer’s comments with the trending topic “Taylor is a magical songwriter.”

Here’s some free advice for John Mayer: Stay away from Adele.

Mayer’s full interview with Rolling Stone is on newsstands Friday.