We here at Stereogum haven’t really gotten into the whole tabloid-bait breakup situation from Taylor Swift and her ex, EDM star Calvin Harris, since it hasn’t really been a music story. (Or, in any case, it hasn’t become a music story yet; one imagines that’ll change when the next Swift album comes out.) But this piece of gossip is too good and weird and, yes, music-related to ignore: According to TMZ, Swift wrote Harris’ current hit, the Rihanna collab “This Is What You Came For,” and she did it in secret.

According to TMZ — which, I hasten to point out, is usually right about this sort of thing — Swift recorded the song as a piano demo. Harris liked it, so Swift and Harris recorded another version of the song in the studio. But they agreed to release a version with Rihanna instead of Swift so the relationship-talk stuff wouldn’t overshadow the song itself. Swift is credited under the sort-of-hilarious pseudonym Nils Sjoberg, and she’s got the publishing rights to the song.

TMZ also claims that Swift got pissed off at Harris when, during an interview, Ryan Seacrest asked Harris if he would ever collaborate with Swift, and he responded with this: “You know we haven’t even spoken about it. I can’t see it happening, though.” Swift got sufficiently annoyed about this that it hastened the couple’s breakup, though Swift has not exercised her option to prevent Harris from performing the song, something Harris has done with a song he made for his ex Rita Ora.

In any case, the whole story serves as further evidence of Swift’s hitmaking powers. Even when she’s off the album cycle, she’s quietly dominating top-40 radio playlists with a song that we didn’t even know came from her. Also, it’s sort of cool to think that Rihanna has now sung a Taylor Swift song.

UPDATE: Harris has now confirmed that Swift wrote it and added that she sang back-up on it:

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

He would go on:

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

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