The "Dark Horse" singer took to Twitter late on Monday -- hours after Swift's interview was published online -- to share a cryptic post about someone being "in sheep's clothing."
Watch out for the Regina George in sheep's clothing...— KATY PERRY (@katyperry) September 9, 2014
Perry's comments are believed to be in response to a remark made by Swift about a very competitive ex-friend about whom she wrote the song "Bad Blood."
"For years, I was never sure if we were friends or not," Swift explained. "She would come up to me at awards shows and say something and walk away, and I would think, 'Are we friends, or did she just give me the harshest insult of my life?'"
"She did something so horrible [last year]," she continued. "I was like, 'Oh, we're just straight-up enemies.' And it wasn't even about a guy! It had to do with business. She basically tried to sabotage an entire arena tour. She tried to hire a bunch of people out from under me. And I'm surprisingly non-confrontational – you would not believe how much I hate conflict. So now I have to avoid her. It's awkward, and I don't like it."
Later in the interview, Swift admits that the problem might have been brought on by "personal" reasons, but states that it wouldn't had happened if she "weren't competitive." Both Swift and Perry have had very public relationships with fellow singer John Mayer.
"Bad Blood" will be included in Swift's upcoming pop album 1989, which will be released on October 27.