Taylor Swift admitted in a recent interview that she wrote her hit song I Knew You Were Trouble with her ex-boyfriend, One Direction's Harry Styles, in mind.

While talking to The Times of London magazine, the 23-year-old songstress explained her performance of the song at the BRIT Awards in February, where Styles was watching from backstage. Her ex-boyfriend watched her perform Trouble and Swift talked about channeling her inner anger while on the awards stage.

"It's not hard to access that emotion when the person the song is about is standing by the side of the stage watching," she said.

She also said about performing that particular song, "You're balancing the analytical side of your brain, which is telling you where to go and how to go there. "With the other side of your brain, which is saying, 'Feel everything you're singing, and show it on your face. Feel everything exactly as you felt it when you wrote the song.' "

At the Sony after-party at London's Arts Club followed the BRIT Awards, Styles commented on his ex-girlfriend's performance by saying, "I thought her performance was really good, she looked great."

One Direction also performed that night and a backstage insider told Daily Mail the singers kept far away from each other to avoid any conflict. Rehearsal schedules were even changed so that the two would not run into each other. One Direction changed set schedules with Mumford & Sons to prevent any drama from potentially occurring.

Watch the video below to see Swift perform I Knew You Were Trouble at the 2013 BRIT Awards.