Raz B only needs two things to get it popping on the "TMZ After Dark" tour ... a girlfriend and a Monster Energy drink.

The B2K rapper hosted our Saturday night tour this past weekend and he had our bus hyped, singing the boy band's throwback hits and sprinkling in some new jams as folks partied all over Hollywood. Play video content

Raz B belted out B2K's "Girlfriend" and previewed the band's upcoming reunion tour ... in between stops at Hollywood hot spots like Saddle Ranch, where everyone got hyped on Monster. Raz B got it going first, and then everyone followed suit with a Monster Energy in hand.

Check out the videos ... "TMZ After Dark" really is the best party in Hollywood, and Raz B took the baton from some of our previous celeb hosts -- like Ray J , Master P , Jerry

See Full Page