Currently being broadcast on BBC Four, the series sees the band visit eight US cities to explore local music history and write and record a song inspired by the stories they hear.

The album is due out in November, and Grohl says he already knows what he wants to do for album number nine. He tells Studio Brussel: "Wait until you see what we're doing for the next record. That's some f***ed up sh*t. I already know what we're doing for that, and it makes this look like f***ing kindergarten."

Grohl also promised the upcoming series of tours for Sonic Highways will make fans happy. He says: "As a live band, the audience is like the sixth member of the band. It's important for us that there's a connection with the audience. When you come see the Foo Fighters, we don't disappoint, I don't think."