Credit: CopettiPhotofab/

Kelly Osbourne has got her groove back!

Just one week after the E! Fashion Police critic, 26, went off on ex-fiance Luke Worrall on Twitter, calling him "the biggest piece of sh**" and saying he was "trying to get back with me" while "f***ing hundreds of girls...behind my back" she's found herself a new man: British musician Rob Damiani, 26.

A source explains Osbourne has "been walking around with a heavy heart" since her July split with model Worrall. Adds the insider, "She spent most of the holidays in the UK lying in bed depressed until her friends finally dragged her out to a club.

Enter Damiani, who's in a band called Don Broco.

"She was standing against a wall not having fun and not really talking to anyone and out of no where a boy came up to her and started chatting her up," the source tells "They were pretty inseparable from that point on."

And though Osbourne is back on the set of her flick So Undercover, she's still in high spirits. "It's like the old Kelly is back," says the insider. "She's happy and glowing!"