Katy Perry
Katy Perry is allegedly devising a plan against Taylor Swift during the Super Bowl 2015 halftime showGetty Images

Katy Perry is allegedly planning to diss Taylor Swift during her performance at the 2015 Super Bowl halftime show, which will take place on 1 February at the University of Phoenix Stadium in Arizona.

According to Hollywood Life, the Roar singer is devising a plan against Swift.

"Katy is in complete rehearsal mode for her Super Bowl performance, she wants to make it feel like a complete party and something that will be remembered forever," a source told the website.

"She wants to make a statement with her performance and show that she is the biggest female act in the world and she wants to show that to everyone including Taylor, who she has a feud with. In Katy's eyes, no one can compete on her level," the insider added.

"Katy will be doing something on stage during her performance that will be directed towards Taylor. She is working on it to be a visual or a lyric related jab," the source continued.

Perry and Swift, who have previously dated John Mayer, were best friends for a long time before things got bad between the two.

During an interview with Rolling Stone magazine, the 25-year-old country singer revealed that the song Bad Blood from her latest album 1989, is about a former friend.

"For years, I was never sure if we were friends or not," she said. "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," Swift went on. "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."

Hours after Swift's cover story hit the internet, Perry posted a cryptic message on Twitter.