The ‘Roar’ hitmaker has been targeted by cyber hackers who broke into her account and sent tweets to her popstar rival.
One tweet to the blonde beauty – who reportedly based her 2014 hit ‘Bad Blood’ on the star’s ongoing feud – said: “miss u baby @taylorswift13 (sic)”
Other tweets made from Katy’s account – which is the most popular on the social media site with 89 million followers – read “shoutout I and r breh” and another simply posted a fist emoji.
The account also tweeted a link to a track on Soundcloud which was an unreleased Katy Perry song called ‘Witness’.
All messages have been deleted however, Romanian-based Twitter user sw4ylol appeared to claim responsibility for breaking into the 31-year-old singer’s account and wrote “#hackersgonnahack(sic)” before they signed off.
Katy and Taylor locked horns two years ago when Taylor accused the brunette beauty of trying to hire her crew for her tour.
She went on to say she had “no interest” in making up with Katy and no plans to build a bridge between them because she “betrayed” her so badly.
Appearing to address the feud, she told said previously magazine: “I’ve trusted people before in friendships or relationships and have felt betrayed.
“If you betray your friend, if you will talk about them badly behind their back, if you will try to humiliate them or talk down to them, I have no interest in having a person like that in my life.”
And she previously revealed a few details about how the pair’s friendship turned sour.
She said: “She did something so horrible. 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.”
Taylor has been unusually quiet on Twitter since she posted a “happy birthday” message to her pal Lena Dunham who turned 30 on May 13.