Taylor Swift Co-Wrote Calvin Harris' Smash Hit 'This Is What You Came For'

Taylor Swift co-wrote ex-boyfriend Calvin Harris' smash hit "This Is What You Came For" under the pseudonym Nils Sjoberg. Jamie McCarthy/Getty, Adam Bettcher/Getty

Taylor Swift co-wrote Calvin Harris and Rihanna's "This Is What You Came For," a representative for Swift confirmed to Rolling Stone. The singer-songwriter used the pseudonym Nils Sjoberg for the song.

TMZ initially reported that Swift had penned the EDM hit, having been revealed by sources connected to the singer. Swift and Harris co-penned the song together during their relationship, though the pair have since broken up.

Harris responded to the news on Twitter, defending his artistic stake in the song: "I wrote the music, produced the song, arranged it and cut the vocals. Initially she wanted it kept secret, hence the pseudonym ... 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." While Harris tried to soften his remarks by calling Swift an "amazing" lyricist, he took a jab by alleging Swift bullied pop star Katy Perry. 

Before the track was officially released, Swift had done some early promotion for the track, wearing a jacket featuring the single's cover art at Coachella. At the time, the track had not even been revealed yet by neither Harris nor Rihanna, who lends her vocals to the song and had previously worked with Harris on the even larger hit "We Found Love."

Though unconfirmed, TMZ further claims that the aftermath of the release is what led to the demise of Swift and Harris' romantic relationship. During a promotional interview for the single on Ryan Seacrest's radio show, the host had asked the producer if he would collaborate with Swift. "You know we haven't even spoken about it," he responded. "I can't see it happening though."

While Swift is reportedly taking a break following the release of 1989 and the subsequent world tour she embarked on for most of 2015, Harris has been slowly unveiling new music and collaborations. He recently released "Olé" with singer John Newman, which many have speculated is a breakup song about Harris' split from Swift told from the perspective of her new suitor, actor Tom Hiddleston, though the song's subject matter has not been confirmed by Harris or Newman.