Katy Perry and Taylor Swift feud: John Mayer's girlfriend releasing revenge song called 1984

American singer/songwriter Katy Perry has taken her feud with American singer/songwriter Taylor Swift to the next level.

The Roar singer registered her new track called 1984 on BMI, which has led fans to think that it is reference to Swift's latest album 1989.

The 25-year-old Red singer and Perry were best friends for a long time before things got bad between the two.

In an interview with Rolling Stone magazine, Swift revealed that the song Bad Blood from 1989, is about a former friend. The two apparently fought over backup dancers.

Perry took a dig at Swift during the 2015 Super Bowl half-time show, which took place on 1 February at the University of Phoenix Stadium in Arizona.

During the performance, the 30-year-old singer's backup dancers wore high-waist polka dot bikinis, something similar to what Swift had worn while holidaying with Conor Kennedy on the shores of Hyannis Port, Massachusetts in 2012.

Meanwhile, in an interview with Billboard, Russell Brand's estranged wife, said she will not let anyone tarnish her reputation.

"If somebody is trying to defame my character, you're going to hear about it [during the performance]," she said.

It was previously reported that American singer-songwriter John Mayer is allegedly helping Perry write a song about Swift.