‘You need someone new to bury like Katy’

TMZ reports that during their relationship, Swift wrote This is What You Came For, sat down at a piano and did a demo into her iPhone. She sent it to Harris, who loved it and so they went into a studio and did a full demo with Swift on vocals and Harris doing the beat.

While TMZ says they both knew the song would be a hit, Swift agreed with Harris that releasing a song together would be a bad move and overshadow the song itself.

So Swift kept the publishing rights but used the pseudonym Nils Sjoberg on the credits.

She reportedly agreed that Rihanna would be a good stand-in to release the song with Harris. It went straight to the top of the chart

This is What You Came For

However, Harris and Swift’s relationship became strained when he responded to a question by Ryan Seacrest about whether or not he would ever collaborate with Swift.

“You know we haven’t even spoken about it. I can’t see it happening though,” he said.

TMZ reports that Swift was hurt, with one source saying it was “the breaking point in the relationship.”

Now, Harris has hit back with a series of tweets in which he starts off admitting that she wrote the song, revealed she sings on it as well and that “she smashed it as usual.”

And she sings on a little bit of it too ?
Amazing lyric writer and she smashed it as usual https://t.co/vW3yGOIJit

— Calvin Harris (@CalvinHarris) July 13, 2016

I wrote the music, produced the song, arranged it and cut the vocals though. And initially she wanted it kept secret, hence the pseudonym

— Calvin Harris (@CalvinHarris) July 13, 2016

Hurtful to me at this point that her and her team would go so far out of their way to try and make ME look bad at this stage though ?

— Calvin Harris (@CalvinHarris) July 13, 2016

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

— Calvin Harris (@CalvinHarris) July 13, 2016

However he pointed the finger directly at Swift and her “team” for leaking the story to TMZ.

“Hurtful to me at this point that her and her team would go so far out of their way to try and make ME look bad at this stage though,” he wrote. “I figure if you are happy in your new relationship you should focus on that instead of trying to tear down your ex bf for something to do.”

He then references her famous feud with Katy Perry, who she reportedly wrote her hit Bad Blood about after the Teenage Dream singer reportedly stole her crew for a tour.

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. I won't allow it

— Calvin Harris (@CalvinHarris) July 13, 2016

Please focus on the positive aspects of YOUR life because you've earned a great one

— Calvin Harris (@CalvinHarris) July 13, 2016

God bless everyone have a beautiful day

— Calvin Harris (@CalvinHarris) July 13, 2016

“I know you are off tour and you need someone new to try and bury like Katy ETC but I’m not that guy, sorry. I won’t allow it,” he wrote. “Please focus on the positive aspects of YOUR life because you’ve earned a great one.”

“God bless everyone have a beautiful day,” he finished with.

The Met Ball was two days after that interview and Swift struck up a spark with Tom Hiddleston, who she is now dating.

Interestingly Swift could stop Harris from performing the song, just like he did to his ex Rita Ora, for whom he wrote I Will Never Let You Down.

Neither Swift nor Harris have commented on the reports.