sunglasses Baltimore Orioles twilight jeans fist Robert Pattinson

After taking a meeting at ICM Agency in LA on Monday, a scruffy Robert Pattinson left the building in a very bad mood -- and he wasn't afraid to show it!

Our photographer kept a respectful distance as he snapped, but all of a sudden Pattinson snapped, clenching his fists and nearly throwing a punch at the camera.

An X17 photographer tells us:

    "Rob already seemed to be in a bad mood as he was leaving ICM and when he saw me, he just snapped. I was just standing there, taking his picture, not saying anything, not getting too close and he just went off. He clenched his fist and got ready to hit me, but his friend told him to stop and calmed him down."

Fortunately the Twilight star backed off when his friend calmed him down and talked some sense into him.

Hey, Rob ... no need to go ballistic on us just for being fans!