David Lee Roth -- Performs 'California Girls' With Beach Boys Singer

David Lee Roth and Mike Love may not be surrounded by California girls anymore ... but that didn't stop them from getting together to sing about how much they still love 'em.

DLR and Love hit the stage with John Stamos at an ELAA Awards benefit in Beverly Hills -- and despite their age (Roth is 59; Love is 72) ... both performers were pretty spry on stage.

David Lee Roth's version of the song was released over 20 years ago.