Taylor Swift and Harry Styles 'officially' dating

Taylor Swift and Harry Styles are "officially" a couple, Mario Lopez confirmed on his radio show Friday night (Nov. 16).

"The X Factor" co-host shared the "inside scoop" about the "Red" singer's guest performance Thursday:

"During rehearsals, Harry from One Direction came and slapped me on the back and said, 'Hey, Mario, how ya doing?' And I said, 'What are you doing here?' And he sort of [pointed] toward Taylor."

But wait, there's more!

The British boy-bander and six-time Grammy winner "walked off hand in hand," says eyewitness Lopez.

Swifty's last romance, with Conor Kennedy, 18, ended in October after a whirlwind summer romance.

But apparently she's moved on to another 18-year-old. (Or moved back -- according to several tabloids, Swift and Styles had a spring fling before One Direction toured Australia in April.)

"So Taylor Swift and Harry from One Direction -- you heard it here first," concluded Lopez. "[They're] officially hanging out, I can say that much."