Stephen A. Smith -- I Rock With 50 Cent ... Awkwardly

Stephen A. Smith is obviously a close personal friend of 50 Cent ... 'cause TMZ Sports has video of the ESPN host taking the stage with Fiddy this past weekend in Vegas and ... it's funny in a good way.

50 was performing at Drai's Friday night when 47-year-old Smith hopped onstage for what we'd like to believe was an audition for membership in the G-Unit.

Check out the clip -- Stephen A. seems to have mastered "what the hell am I doing up here" swag ... 'cause 50 doesn't seem bothered with him being in the crew ... even though he looks like someone's uncle.