Johnny Depp's girlfriend Amber Heard has rallied behind fiance's musical career as the "Pirates of the Caribbean" star jammed with rock band Aerosmith.

During the Aerosmith's concert at the Xfinity Center in Mansfield, Mass., Johnny Depp's girlfriend Amber Heard was in attendance to support her man who joined Steven Tyler and Tyler Perry on stage during an encore, E! reported.

The 51-year-old actor popped on stage and strummed the guitar while the band performed "Train Kept a Rollin.

"The star-studded musical moment was made possible by the fact that Depp is currently filming Black Mass, the upcoming movie about Whitey Bulger, in the area," the website added.

Johnny Depp's girlfriend Amber Heard was backstage looking on while the crowd "went nuts."

Johnny Depp's doing a cameo performance on Aerosmith concert was not unprecedented. Back in August 2012, the "Transcendence" star also joined the band on stage during the Hollywood Bowl concert.

In December of that same year, the actor played "Come Together" and "Stop Messin' Around" with Aerosmith.

In an earlier report by RadarOnline, Johnny Depp's girlfriend Amber Heard might be making him happy, but his friends are worried that he's not totally over his partying ways.

"Johnny was so wild for so long and it's hard to believe that Amber has straightened him out completely," an insider told the tabloid site. "Last year he was partying with six chicks and getting turned away from bars, this year he's quietly going to dinner with Amber and you never see him do anything wrong."

The source credited Johnny Depp's girlfriend for reining in his wild ways but the actor's attitude has always been to have fun.

"Johnny always seemed like he was having a great time out partying, and it wasn't just because a lot of women were around. People are afraid that he's just stopped partying or is hiding his partying to be a good and upstanding guy for Amber," the tabloid added.