Say it ain't so! One Direction heartthrob Harry Styles was spotted at 'X Factor' rehearsals ... with Taylor Swift.

E! Online reports that Styles, 18, was palling around with Swift, 22, at the Los Angeles studios, where Swift was rehearsing for tonight's (Nov. 15) live show. A spy said today, "Harry is there with her now. She is doing rehearsals this afternoon. And he is in her group. He watched her onstage going through her performance. He was sitting with her mom and the rest of her entourage."

The pair got flirty, not just friendly, from the sounds of it. "After she finished, he went up to the stage. They were joking and laughing," the sources added. "He picked her up and threw her over his shoulder and carried her off."

This report comes on the heels of Swift being spotted wearing an airplane necklace that's identical to the one Styles usually sports. The pair were linked back in the spring, but Swift reportedly ended it when Hazza was photographed locking lips with model Emma Ostilly. Maybe he really did have a private dinner scheduled with T-Swizzle.

However, don't expect Harry to confirm the rumors. He's been consistently saying he's single throughout the entire 'Take Me Home' press tour ... and if Swift's track record is any indication, he'll probably stay that way, but not likely before she puts a down payment on that London home.

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