After years of ambiguity, Katy Perry finally let the truth behind her bad blood with Taylor Swift spill in May, when she confirmed to James Corden that Swift was definitely not her friend. So what finally made Perry decide to come clean? In a new interview with NMEshe says she'd simply reached a breaking point.

Perry, whose Witness is inching closer to release, told Corden during a round of Carpool Karaoke that she initially tried to settle discord with Swift in private, but that the country-gone-pop singer ignored her and released the cutting "Bad Blood" — which was aimed at Perry — instead. And after letting resentment stew, Perry finally said she'd had enough.

"I mean, I'm not Buddha — things irritate me," she told NME. "I wish that I could turn the other cheek every single time, but I'm also not a pushover, you know? Especially when someone tries to assassinate my character with little girls. That's so messed up!"

Perry confirmed during her Carpool Karaoke appearance that the feud with Swift developed from an argument over background dancers, and insinuated that retaliation might be coming.

"What I want to say is that I'm ready for that B.S. to be done," she said. "Now, there is the law of cause and effect. You do something, there's going to be a reaction — and trust me, daddy, there's going to be a reaction! It's all about karma, right?"

Cutting Celeb-on-Celeb-Disses: