LeBron James Greeted By Marching Band ... At Vegas Nightclub

It was like a scene from "Rocky III" ... LeBron James walked into a Vegas club Monday night complete with his own marching band and fireworks -- and the crowd went insane!

It all went down at Marquee at the Cosmopolitan hotel -- where the club hosted a Cavs championship celebration for King James.

LeBron -- following his own party advice -- got on the dance floor and jammed out to Drake's "Forever."