Watch out Taylor, you’ve ticked off the wrong people! Katy is reportedly ‘determined’ to one-up Taylor’s ‘Bad Blood’ diss song with an even better revenge song of her own — and she’s apparently getting help from John Mayer, who dated both of them!

Oh snap, this feud is about to be turned up a notch! Seeing Taylor Swift, 25, debut her “Bad Blood” music video with all of her girls at the Billboard Awards on May 17 was the last straw for Katy Perry, 30, who is said to be the subject of the diss tune. Now, she’s enlisted the help of John Mayer, 37, to retaliate in the form of an epic revenge song, according to a new report — find out Katy’s plan to finally get back at Taylor!

John Mayer & Katy Perry’s Taylor Swift Revenge Song?

“Katy thinks revenge is a dish best served cold. She’s even more determined to show people what she calls ‘the real Taylor’, she’s writing some big, anthemic-type songs that’ll feature dirt on Taylor that John’s told her from when they used to date,” a friend of Katy’s told HEAT.

Wow, this feud is getting pretty intense! Is it wrong of us to say we’re slightly excited to hear this revenge song? What kind of dirt does John have on Taylor?! We need to know!

As for Katy’s absence at the Billboards, her friend said “John convinced her it was a bad idea. Katy realized she couldn’t stand the idea of the cameras being on her face as she had to watch Taylor win every award with all her friends applauding her.”

Having to miss the awards was probably the last straw for Katy! Her friend added, “Katy’s sure that she’ll be back on top before long, and Taylor will regret ever starting this stupid row.”

Taylor Swift & Katy Perry Feud

In case you’re a bit lost as to why these two pop stars hate each other, we’re here to break it all down for ya!

After touring with Katy Perry’s California Dreams world tour in 2011, three backup dancers auditioned and made it on to Taylor Swift’s world tour for her album Red. Mid-tour with Tay, the dancers got an offer to leave the tour to re-join Katy on her Prism tour and they agreed to leave Taylor!

Ever since then, Taylor has been super salty and if you listen to her song “Bad Blood” with the back-up dancer situation in mind, it totally makes sense that the song is about Katy!

And now it looks like this feud isn’t slowing down any time soon with Katy’s rebuttal with John Mayer’s help! HollywoodLifers, do you think Katy’s revenge song is going to be good? Let us know your thoughts in the comments below!

— Shira Benozilio