The 23-year-old British singer appeared to confirm in an interview with BBC Radio One that his new song "Two Ghosts" is about the 27-year-old American pop star.
"I mean, I think it's pretty self-explanatory," Styles said of the track before entreating manager Jeffrey Azoff. "Help me, Jeffrey!"
"It's about [how] sometimes things change. You can do all the same things, but sometimes it's just different," he reluctantly added.
"Two Ghosts" includes the lyrics, "Same lips red, same eyes blue/Same white shirt, couple more tattoos/But it's not you, and it's not me." Styles said at an iHeartRadio concert Wednesday that he penned the song in late 2013.
"This is the one song from the album that wasn't written last year. I wrote it three and a half years ago," he shared, according to Elle.
Styles and Swift split in January 2013 after a few months of dating. The One Direction singer reflected on the short-lived romance in the May 4 issue of Rolling Stone.
"When I see photos from that day," he said in reference to paparazzi shots from their second date, "I think: Relationships are hard, at any age. And adding in that you don't really understand exactly how it works when you're 18, trying to navigate all that stuff didn't make it easier."
"It was a learning experience for sure. But at the heart of it -- I just wanted it to be a normal date," the star added.
"Two Ghosts" appears on Styles' debut solo album, Harry Styles, which dropped Friday.