Proving that a showbiz feud is nothing if not bitter, Katy Perry and Taylor Swift appear to be - STILL - at loggerheads.

Ms Perry, 32, has today released her much-anticipated new album, Witness. It includes hits such as Chained To The Rhythm and Bon Appétit and has fan all-sorts of excited as it's the star's first album since Prism FOUR years ago. So far, so standard, you say. However, in an intriguing twist a certain Taylor Swift - she of the long-running feud with Katy - has made a pretty spectacular announcement of her own. Yes, after years of refusing to put her music on Spotify, Tay-Tay last night released ALL of her albums onto the world's leading music-streaming platform. Coincidence? Probably not (though we'll let you be the judge). There was no promotion of this milestone move by Ms Swift, nor does Thursday, June 8 seem to have any real significance for her. Still, predictably Twitter has been having a field-day in the aftermath.

I think we all can agree Taylor Swift is the most immature artist of all time

— ️ (@roarsus) June 9, 2017

taylor swift putting her music back on spotify because katy perry is releasing her album tonight is the level of petty i aspire to be

— jasmyne (@jasmynexv) June 9, 2017

taylor swift's the kind of person who'd go into labor at someone else's baby shower or announce her engagement during someone else's wedding

— aillah | nsfr (@thranduiIien) June 9, 2017

*Katy Perry drops a new album & Taylor Swift puts her music back up on Spotify & other streaming sites*

*SZA drops #CTRL the same night* ? pic.twitter.com/nR8twZ2h5q — Matthew A. Cherry (@MatthewACherry) June 9, 2017

It's hard to pick sides in the Katy Perry/Taylor Swift feud because they both don't have a point.

— Louis Virtel (@louisvirtel) June 9, 2017

I always defended but today I realized, Taylor Swift is a REAL snake. She's so imature.? Always try to play victim#TaylorSwiftIsOverParty

— Its my Birthday ?? (@GagaNewsShade) June 9, 2017

Taylor Swift uploading her Albums to Spotify like pic.twitter.com/iAk3baO0Sg

— dominos papi (@sadhoeflo) June 9, 2017

in other news - taylor swift chose katy perry's album release date to pop her entire back catalogue on spotify. this is petty af and i ❤️ it

— Emily Hier (@emilyhier) June 9, 2017

Katy : I will release my Album tomorrow! Stay tune ! Taylor swift : Let's upload all of my albums back to Spotify.#KatyPerry #KPWWW

— Gilang Satria R (@G_satria24) June 9, 2017

Promoting Witness, Katy has been chatting about her dispute with Taylor (we won't go back into the nitty-gritty - something about one of them/both of them 'stealing' dancers for a world tour). Referring to 'the incident,' Ms Perry told James Corden last month: “That’s true, there is a situation. Honestly, it’s really like she started it and it’s time for her to finish it. "I’m not Buddha – things irritate me," she continued. "I wish that I could turn the other cheek every single time, but I’m also not a pushover, you know? Especially when someone tries to assassinate my character with little girls. That’s so messed up!"