Foo Fighters and Zac Brown UNITE for “War Pigs” Cover

The Foo Fighters are hanging out for a full week of “Late Show with David Letterman” episodes to promote their new HBO show, “Sonic Highways.” Each night will feature a classic rock cover inspired by the documentary series.

And the kickoff was EPIC, with the Foos joining guests Zac Brown for a cover of the Black Sabbath song “War Pigs.” (Letterman introduced the segment like this: “Zac Brown. Black Sabbath. Foo Fighters. I don’t know, what do you kids want from me?” He’s definitely doing his part.)

The HBO series chronicles the making of the latest Foo Fighters album, also called “Sonic Highways,” which was recorded in eight different cities with significant ties to the history of American rock music. (They include Los Angeles, Nashville, Seattle and Austin.) It also features interviews with artists about the significance and history of these musical communities, such as Dolly Parton, Slash and LL Cool J.