Members of Metallica, Iron Maiden and the Foo Fighters recently held a jam session together, and there’s a picture to prove it.

Jam sessions have existed for as long as people have been playing instruments. Getting a group of musicians together to improvise, play off one another and generally rock out is at the essence of songwriting. Still, when the group is made up of some of the biggest names in music, it’s worth getting excited about.

Guitarist Howie Simon (a former member of Alcatrazz and Jeff Scott Soto) shared a photo on Instagram featuring Rob Trujillo, Adrian Smith and Taylor Hawkins jamming together. Richie Kotzen (formerly of Poison, currently in the Winery Dogs) rounded out the ensemble, which you can see below.

"Sometimes at parties I jam with the bass player from Metallica, the drummer from the Foo Fighters, the guitarist from Iron Maiden and my friend Richie," Simon wrote. "I hope I'm not name dropping! Such a fun time -- they always throw the best parties!”

The picture was accompanied by a series of hashtags, including one that said #Birthday, making us believe this session was more of a one-time-only celebration rather than a regular occurrence.

Still, the Foo Fighters have covered Metallica in the past and both bands have a history of mutual admiration. Couple that with the fact that both are performing at the Chris Cornell tribute concert in Los Angeles on Jan. 16, so perhaps a future collaboration is not so far-fetched.

Check out upcoming tour dates for Metallica here, Iron Maiden here and the Foo Fighters here.