Here are the first pix of Brad just after the incident an hour ago that caused him to fall from his bike in the middle of Hollywood traffic.

Pitt lost his balance, hit the bumper of the car in front of him, and fell off his new motorcycle. He got up, pulled his bike to the side of the road, and sought shelter inside a nearby building.

But before going inside, he confronted the photographer who cut him off just moments before the accident. It appears that action shook Brad and caused him to lose his balance just a half a block down the road.

We'll have more details coming in and the video's coming soon. Stay tuned ... and in the meantime, check out the gallery below for the blow-by-blow.