He and Fugazi mainman MacKaye are among the stars interviewed for Salad Days, which investigates the Washington DC hardcore punk scene that spawned Minor Threat, Bad Brains, Void, Henry Rollins' State Of Alert and many others. It focuses on the music, people and records that changed the course of music history.

In the trailer, Grohl says: "I have heroes that I would get nervous around. I know Ian and HR are just normal dudes, but those f***ing people changed my life."