Taylor Swift used her only full 2016 show to make a statement about her former boyfriend Calvin Harris, by singing the song she wrote for him.
The performer turned heads at the Formula 1 United States Grand Prix as she sang This Is What You Came For, which she wrote for Mr Harris under the pseudonym Nils Sjoberg whilst they were dating.
The hit was released in April, and featured vocals from Rihanna.
Ms Swift's last full concert was in December of last year, and fans waited many months to see her perform live again.
She played on Saturday night to a crowd 80,000 strong, singing her well-known hits as well as the Calvin Harris song.
After Ms Swift's representatives confirmed in July she had penned the song for Calvin Harris, the two had a very public feud.
The producer accused her of trying to "bury" him in a bid for publicity.
Mr Harris, who split with Swift shortly before she struck up a new relationship with actor Tom Hiddleston, said he was "hurt" by reports that the lyrics to one of his songs had been written by her.
Saying he would have happily given her full credit, he took to Twitter to protest against Swift's team attempting to make him "look bad" in public.
He also revealed some of the vocals on the track were performed by Ms Swift.
Mr Harris said "And she sings on a little bit of it too. Amazing lyric writer and she smashed it as usual.
"I wrote the music, produced the song, arranged it and cut the vocals though. And initially she wanted it kept secret, hence the pseudonym."
He also accused her of trying to tear your ex bf down" for "something to do".
Ms Swift and Mr Hiddleston ended their fling in September after a series of very public displays of affection.
"She was the one to put the brakes on the relationship," a source close to the couple told Us magazine.
"Tom wanted the relationship to be more public than she was comfortable with.
Taylor knew the backlash that comes with public displays of affection but Tom didn't listen to her concerns when she brought them up."