Taylor Swift performed for the first time this year at the Formula 1 U.S. Grand Prix in Austin, TX on Sunday evening — and no one expected the number she chose to perform. She took to the piano to sing a medley version of “This is What You Came For,” you know… the song that her ex-boyfriend, producer Calvin Harris made with Rihanna.

Calvin and Taylor split up over the summer and it was later revealed that Taylor actually co-wrote the smash hit under a weird alias, Nils Sjöberg. Many think that this performance was Taylor’s way of subtly throwing shade at her ex. We think she just performed a song she wrote. Afterall, Taylor is not known for being a proactive participant in her beefs. Just ask Kanye.

Check out the performance below.

Congrats are also in order for the songwriter, whose self-titled debut album was released 10 years ago, today!