Bruce Jenner was the awkward old guy at the club this weekend ... bro'ing out with son Brody as he DJ'ed a gig in Hollywood.
Brody was working an event on Sunday in Los Angeles at XIV's Summer Sessions for Frankie Delgado's birthday. The theme was "Mexican fiesta" where the crowd was encouraged to wear neon and very little else.
Jenner -- who is separated from Kardashian family matriarch Kris Jenner -- can be seen in the video holding a beer ... with just the slightest head bob going on.
Get some, Bruce.