AceShowbiz -

Katy Perry addresses her "Mean Girls" tweet which was reportedly aimed at Taylor Swift. "If somebody is trying to defame my character, you're going to hear about it," she said in Billboard's latest issue ahead of her performance at the Super Bowl.

Last year, Perry tweeted a cryptic message which referred to Rachel McAdams' snobby character in the popular 2004 teen comedy. "Watch out for the Regina George in sheep's clothing..," she wrote after Swift supposedly dissed her in a Rolling Stone interview.

Back then, the country/pop singer talked about inspiration behind her song "Bad Blood". She confirmed it's about a fellow female singer, "For years, I was never sure if we were friends or not. 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?' "

"[Then last year] she did something so horrible. I was like, 'Oh, we're just straight-up enemies.' And it wasn't even about a guy!" she continued. Without giving any name, the "Shake It Off" hitmaker explained, "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."