LeBron James: After-Party Ultimatum ... 'Dance Or Get the F*** Out'

LeBron James issued a VERY SERIOUS warning to his ESPY after-party guests Wednesday night -- either you dance or "get the f*** up out of here!!!"

FYI, this video is awesome!

Bron took the stage at the Uninterrupted party at Le Jardin -- and made it clear he had no patience for the bougie Hollywood people who are too uptight to turn up.

"If you not dancing, shaking your ass or having a good time ... there's an exit sign right there!"

"So if ya'll not dancing having a good time shaking your ass ... ya'll got to go man."

By the way, the party was INSANE -- with a performance by Kendrick Lamar ... and SO MUCH DELICIOUS FOOD!!!!

Seriously ... check out this clip of DJ K-Love with his to-go plate -- "It's like mini-Thanksgiving dinner in that motherf****r right now!"