“I had to literally do a double-take,” an onlooker tells PEOPLE of finding Styles, 18, with Swift, 22, on the set of The X Factor Thursday morning.
Styles was on hand to watch Swift rehearse the debut of “State of Grace,” which she performed later that night on the Fox reality show.
“He was smiling at her while she rehearsed. When she was done he jumped up on stage, picked her up, put her over his shoulder and carried her off stage,” the onlooker says. “The whole crew was really surprised.”
The young singers were also spotted by X Factor host Mario Lopez, who says he was slapped on the back by Styles during Swift’s rehearsal.
“I said, ‘What are you doing here,’ ” Lopez said on his 104.3 MY FM radio show Friday. “And he sort of [pointed] toward Taylor.”
Lopez went on to say he later saw the two “hand-in-hand.”
A telling sign of the budding relationship may have been a look Styles shared with his bandmate Niall Horan a week earlier after Horan told PEOPLE his favorite song of 2012 was Swift’s “Never Ever Getting Back Together.”
When asked if he would ever date Swift, Horan gave a small laugh, looked at Styles and answered with a succinct, “no.”
Oh good grief. Can’t wait to see how this one plays out. I mean, do you realize that Taylor Swift‘s dated the following people: Joe Jonas, Taylor Lautner, John Mayer, Cory Monteith, Toby Hemingway, Jake Gyllenhaal, Zac Efron, Garrett Hedlund, Eddie Redmayne, Conor Kennedy, and now, One Direction’s Harry Styles. Who’s next? Is there many top-notch young men out there who haven’t dated Taylor Swift, or who, at least, haven’t been pursued by her? I’m not calling her a slut by any means, because damn. Those are some enviable dudes (Taylor Lautner, Jake Gyllenhaal, and Garrett Hedlund are definitely most impressive) and you know what? F-ck these backhanded little songs that she writes and performs—I want her to write a damn book detailing this this, because seriously. You just can’t make it up. Know what she should title it, too? I’m thinking something like this: ‘The Girl With the Golden Gitch’. That sounds about right.