Taylor Swift Just Sang Ex Calvin Harris’ Song ‘This Is What You Came For’—and Swifties Have Theories

Before there was William Bowery, there was Nils Sjöberg. On June 13, Taylor Swift revived her famous pseudonym at her second Eras Tour performance in Liverpool, England.

That’s right, during her latest surprise set, Swift broke out “This Is What You Came For,” the 2016 hit she wrote with then-boyfriend Calvin Harris. The popular DJ released the song with Rihanna while he was still dating Swift, though she wasn’t publicly credited as a writer at the time.

Instead, she assumed the name Nils Sjöberg—a move Swift’s ex-boyfriend Joe Alwyn would later mimic with the pseudonym William Bowery for multiple Folklore and Evermore tracks. And while Swift eventually confirmed her identity after her split from Harris, she has only performed the pop banger on two reported occasions: Once at the Formula 1 Grand Prix in November 2016 and then at a pre-Super Bowl event in February 2017. Seven years later, she’s bringing it back.

“Every single time I have an acoustic set, I’m always trying to think of things you might want to hear—maybe things that might be a little bit unexpected,” Swift told the crowd before breaking into a mashup of “This Is What You Came For” and “Gold Rush,” per fan-recorded videos. “Let’s see how we did tonight.”

Taylor Swift performs in Liverpool, England.

Gareth Cattermole/TAS24/Getty Images

Unexpected is definitely the right word. “I DIDN’T THINK SHE WOULD EVER SING THIS,” one fan commented on a TikTok video of the performance, while another wrote “THE BIGGEST SHOCK EVER.” Others predicted the song will might get the “Taylor’s Version” treatment on the eventual Reputation re-recording, which Swift has already promised will be “fire.”

“THE LIGHTS ON THE WRISTBANDS ARE GREEN THIS IS SO GONNA BE A VAULT SONG ON REP TV,” one fan noted, while another wrote, “She said ‘and that’s mine too.’”

Taylor Swift and Calvin Harris dated for 15 months before their split in May 2016, which is when things got messy. While Swift initially opted to pen the lyrics and sing backup vocals for “This Is What You Came For” in secret, her team confirmed the rumors about her pseudonym a month after their breakup—and Harris was not happy about it. Though he initially praised the singer’s contribution to the record, he followed it up with a full-fledged Twitter rant accusing his ex of trying to make him “look bad” while taking swipes at her fling with Tom Hiddleston.

“I wrote the music, produced the song, arranged it and cut the vocals though,” Harris wrote in the since-deleted thread from June 2016, which can still be read here. “And initially she wanted to keep it secret, hence the pseudonym.” He described her decision to confirm the initial TMZ report about their collaboration “hurtful,” adding, “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.”

He later said he regretting his words in an interview with British GQ. “It was completely the wrong instinct,” he said in 2017, per Buzzfeed. I was protecting what I see as my one talent in the world being belittled. It felt like things were piling on top of me and that was when I snapped.”

He continued, “It’s very difficult when something I consider so personal plays out very publicly. The aftermath of the relationship was way more heavily publicized than the relationship itself. When we were together, we were very careful for it not to be a media circus. She respected my feelings in that sense. I’m not good at being a celebrity. But when it ended, all hell broke loose. Now I see that Twitter thing as a result of me succumbing to pressure. It took me a minute to realize that none of that matters. I’m a positive guy. For both of us it was the wrong situation. It clearly wasn’t right, so it ended.

As for Swift’s perspective, many fans believe her Lover track “I Forgot That You Existed” was inspired by Harris. “How many days did I spend thinking ‘bout how you did me wrong, wrong, wrong?” she sings in the opening verse. “Lived in the shade you were throwing ’til all of my sunshine was gone, gone, gone.”

Just before the chorus, she continues, “But then something happened one magical night…I forgot that you existed. And I thought that it would kill me, but it didn’t. And it was so nice. So peaceful and quiet. I forgot that you existed. It isn’t love, it isn’t hate, it’s just indifference.”