Either he's jet lagged from London or still down in the dumps over that heated exchange with estranged wife Jennifer Garner earlier this week!

On Friday night Ben Affleck arrived at Los Angeles International Airport, and the actor looked exhausted -- and like he's put on a few pounds. Whatevs, he's still a stud, and he also made the time to greet fans and sign a few autographs, so we totally adore him for that!

Still, we're dying to know what happened when we photographed Ben and Jen having a VERY tense reunion at the kids’ karate class last week. After having a discussion about something, Jen was seen wiping tears from her eyes, and Ben had a pretty guilty look on his face. I mean, he's already (allegedly) banged their former nanny, so what's he done now?!