Well, the cat fight's officially out of the bag.

Appearing in a Carpool Karaoke segment with James Corden on The Late Late Show Monday night (May 22), Katy Perry dropped the mic, and the details, on her and Taylor Swift's feud.

"That's true, there is a situation," the "Swish Swish" singer admitted to Corden when asked about the long-rumored "Bad Blood" between her and Swift.

"Honestly, it's really like she started it and it's time for her to finish it," Perry added, claiming that she "tried to" talk to the 1989 pop star, who was unwilling to work things out. "She wouldn't speak to me. I do the right thing anytime that it feels like a fumble. It was a full shut-down and then she writes a song about me and I'm like, 'Okay, cool, cool, cool. That's how you wanna deal with it?'"

"But, what I wanna say is that I'm ready for that B.S. to be done," the Witness singer continued. "Now, there is the law of cause and effect. You do something and there's going to be a reaction. And trust me daddy, there's going to be a reaction. It's all about karma."

And karma seems to be on the way, indeed: Aside from "Swish Swish," a song many are calling a "diss track" against Swift, Perry's upcoming album also features a collaboration with Kanye West called "Cold Hearted Snake" (a reference to the Kim Kardashian/Kanye/Taylor "Famous" saga, perhaps?). The pop star also appears on Swift's ex Calvin Harris' upcoming album.

Petty is as petty does.

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