Watch Harry Styles Sing Part of Ex-Girlfriend Taylor Swift's '22'

The pair dated between 2012 and 2013.

Harry Styles is feeling 22! During the 28-year-old singer's One Night Only concert in London, Styles delighted the crowd when he sang part of Taylor Swift's 2012 track, "22." The singers dated between 2012 and 2013.

The moment happened when a fan in the crowd told Styles that she was at the concert celebrating her 22nd birthday. He responded by exclaiming, "22!" before quietly singing some of Swift's lyrics.

"I'm feeling 22," Styles crooned to cheers from the crowd.

Styles' ex recently came up in conversation when he appeared on SiriusXM's The Howard Stern Show. During the chat, the host asked the singer about the fan theory that his new song, "Daylight," is a nod to Swift's 2019 track of the same name.

"Here we go," Styles quipped when Stern brought up the twin titles, before telling the radio host of his Swift theory, "You're reading too much into it. I'd love to tell you you're spot on, but no, sorry."

Both Swift and Styles have moved on from their brief romance, as Swift has been in a years-long relationship with actor Joe Alwyn, and Styles has been linked to Olivia Wilde since he starred in Don't Worry Darling, a movie she directed.

"When they first started dating, they were together every day because they were filming and in a pandemic bubble. When life started to return to normal and their schedules filled up again, they made a conscious effort to not get complacent," a source told ET earlier this month of Styles and Wilde. "They treat their relationship with a lot of respect and work on it like they would their careers."