The 49-year-old actor plays guitar on the group's upcoming album Music from Another Dimension! and he joined them for a special performance during their show at the Hollywood Bowl, reported MTV online.
Frontman Steven Tyler introduced the star to the stage, telling the crowd, "I need a little help up here. Johnny Depp, are you in the house?" Depp then walked on and played guitar on classic track Train Kept A-Rollin' for a crowd which included Tyler's actress daughter Liv and funnyman Jim Carrey.
After the concert, Depp joined the band for an afterparty at a Mexican restaurant on the Sunset Strip with other famous faces including Alice Cooper and Breaking Bad star Aaron Paul.