Justin Bieber is continuing his downward spiral into WTF-dom. And we've gotta admit, it gets more entertaining by the day.

After the Biebs emerged from a hospital in Central London where he was convalescing for breathing related problems, the paparazzi were waiting outside to talk to him. Like they do.

So of course he lunged and threatened to "beat the f---" out of one of them.

Seems that Bieber, with the help of his bodyguards, pushed past the photogs to get into a waiting SUV -- but one of them didn't like being handled in such a way and he immediately started yelling that he was assaulted and Justin should go back to America.

The impressive British (and American) cursing apparently worked, because the Biebs jumped out of the SUV and came for the photographer, expletive-filled yelling and all.

“What the f--- you say? I'll f---ing beat the f--- out of you," he was able to get out before his handlers shoved him back in the car.

TMZ has the uncensored version of the video. Just keep in mind it's NSFW unless you work in an environment where F-bombs are dropped on the regular. Like maybe the DMV.

Justin later tweeted about the whole event (of course) explaining it away by saying he was just having a rough morning and the photog got the best of him.

Well, sure. Don't all YOUR rough mornings start off by being held back by bodyguards when you want to punch a photographer's face in?