Holly Montag Dating Audrina Patridge's Former Flame

Ah, the revolving romance door of The Hills cast. The newest recycled bachelor? Justin "Bobby" Brescia -- the shaggy-haired aemotional ex-boyfriend of Audrina Patridge. Word has it he's romancing Heidi Montag's more interesting sister, Holly Montag.

"They're dating and have been for awhile," a source told Us.

Holly is a slightly well received stand-up comedian, while Brescia doesn't do much of anything. One insider thinks the relationship stands on shaky foundation. Not a shock to anyone who's watched the commitment-phobe's womanizing ways.

"He's reckless and will disappear in his house for days at a time," the source says. "He's not reliable."