Taylor Swift probably wants to know why John Mayer has gotta be so mean.

Taylor called out the rocker lothario with her 2010 song "Dear John," and he is now returning the favor by slamming her in his new song, "Paper Doll," according to Hollywood Life.

In the song, John compares Taylor to a paper doll (hence, the song name) and suggests that she's two-faced.

Check out a sample lyric from John's tune: "You’re like 22 girls in one / And none of them know what they’re running from / Was it just too far to fall for a little paper doll?" Ouch.

This is clearly a reference to Taylor's recent hit single, "22."

In another lyric from the new song, John sings, ”Someone’s gonna paint you another sky.” This appears to be a response to Taylor's 2010 lyric, “You paint me a blue sky and go back and turn it to rain.”

In "Dear John," Taylor criticized John for his "dark, twisted games." Apparently, he didn't appreciate that.

The two dated briefly back in 2010.

We're used to musicians going back and forth with diss tracks in the rap world, but not necessarily in the singer-songwriter community.

Source: Hollywood Life