The movie star has been filming the Whitey Bulger biopic Black Mass in Boston for the past few months, and on Wednesday he took some time off to attend the rock band's concert at the Xfinity Center in nearby Mansfield.
During the encore, frontman and Massachusetts native Steven Tyler asked the crowd to give a warm welcome to his surprise guest, and exclaimed, "Yo! Bringing out on stage my good friend, Mr. Johnny Depp!"
Depp strapped on his guitar and came out to join Aerosmith for their classic song Train Kept A-Rollin, and the actor even played an extended solo during the performance.
This isn't the first time Depp has collaborated with the rockers for the track - he played on the studio version of the song, which featured on their 2012 album Music From Another Dimension! He also played the track live in concert during shows the same year.
Last month (Jun14), Depp also made a surprise appearance at music icon Willie Nelson's gig in Boston by playing guitar with the singer's Family Band.