Katy Perry did not hesitate to take a dig at Taylor Swift during her performance at the 2015 Super Bowl half-time show, which took place on 1 February at the University of Phoenix Stadium in Arizona.

The 30-year-old singer's backup dancers wore high-waist polka dot bikinis during her performance of California Gurls.

In 2012, the 25-year-old country crooner was spotted wearing a retro, red two-piece with white polka dots, while holidaying with Conor Kennedy on the shores of Hyannis Port, Massachusetts.

Twitter users were quick to catch on Perry's diss at Swift.

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

During an interview with Rolling Stone magazine, the Red hitmaker had 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."