The cameo appearance came during J Balvin's Sunday night set ... who took the stage in full Agent J costume. After yelling "Coachella!!" Smith went right into rapping the words to "Men in Black ...

Reggaeton star J Balvin stunned his Coachella audience by ... He then rapped the track as backing dancers in alien costumes and black suits performed behind him. At the end of the song, Balvin ...