It's Taylor Swift vs. Katy Perry round 23.

After Taylor didn't exactly hide that her hit song, "Bad Blood," was about the 30-year-old singer, it looks like Katy is answering back with a not-so-veiled new song titled "1984." Taylor's latest album, of course, is titled 1989, the year of her birth.

Katy recently officially registered "1984" with her music publisher, BMI. However, she's not listed as a writer on the new song, which credits Austin Dallas, Carlsson Andreas Michael, Collier Patrick, and Tokio Mazerine. Katy has worked with Carlsson before, who co-wrote her 2009 hit "Waking Up In Vegas."

PHOTO: New 'Bad Blood?' Taylor Swift's Besties Lorde and Ellie Goulding Hang With Katy Perry

The "Teenage Dream" singer hasn't been shy about biting back against Taylor before. Back in September, the pop star tweeted: "Watch out for the Regina George in sheep's clothing..." and later confirmed to Billboard magazine that she was calling out the "Blank Space" singer with her Mean Girls reference.

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"If somebody is trying to defame my character, you're going to hear about it," Katy told the magazine in January. She was obviously referring to Taylor's comments to Rolling Stone that "Bad Blood" was about a pop star nemesis, who tried to "sabotage" her whole arena tour.

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Just don't ever expect Taylor, who also dated Katy's on-again/off-again boyfriend John Mayer before her, to have it out with Katy in public.

PHOTO: Ellie Goulding Explains Why She Deleted THAT Katy Perry Pic

"I'm not giving them anything to write about," Taylor told the Telegraph in March about the reported feud between the two pop superstars. "I'm never going to talk about her in my interview. It's not going to happen."

Revisit Taylor and Katy's drama.

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