DJ Calvin Harris has caused controversy after revealing the list of artists he will be working with on his next album.
The Scottish producer, 33, will be teaming up with Katy Perry, among others, on his forthcoming LP Funk Wav Bounces Vol. 1, which he announced on social media on Tuesday.
Of course, music fans will know Perry, 32, has a well-documented feud with Harris's ex-girlfriend Taylor Swift, dating back to at least 2014.
Swift, 27, referred to an unidentified 'mean girl' in a Rolling Stone interview three years ago, largely recognised as Perry.
It is widely believed that Perry is also the subject of Swift's 2015 song 'Bad Blood'.
Perry has attempted to remain more mature when it comes to the war of words, but when asked if she would work with Swift in future, she replied: "If she says sorry, sure."
Harris himself confirmed the rift between the pair when he lashed out at Swift on Twitter in July 2016 - a few weeks after the pair ended their 15-month relationship and she immediately started dating actor Tom Hiddleston.
He tweeted: "I figure if you're happy in your new relationship you should focus on that instead of trying to tear your ex bf down for something to do.
"I know you're off tour and you need someone new to try and bury like Katy ETC but I'm not that guy, sorry."