Jim Carrey Rebounds and Scores ... with Hot Brunette

10/12/2010 8:00 AM PDT
Jim Carrey cracked the biggest smile on the planet at a rooftop party in NYC this past Saturday -- and we're guessing it had a lot to do with that smoking hot brunette in his arms.

It's been 6 months since Jim called it quits with Jenny McCarthy ... and it's pretty clear he's over the blonde phase ... for now.

No word yet on the identity of the mystery woman -- but based on the photo, Jim's face says it all ... "Jenny who?"

Alrighty then.