Foo Fighters and Zac Brown Cover Black Sabbath's "War Pigs" on 'Letterman' —Video

Last night, David Letterman's Foo Fighters Week got off to an odd start when Zac Brown teamed up with Foo Fighters to cover Black Sabbath's "War Pigs" on The Late Show With David Letterman.

"Well there, you see, that's what we're talking about," Letterman said. "Zac Brown. Black Sabbath. Foo Fighters. I don't know, what do you kids want from me?"

Before the performance, Grohl sat down with Letterman to discuss his 8-year-old daughter's love of Amy Winehouse and rap, plus the music Grohl's parents played when he was his daughter's age.

"We would listen to Candide, then Neil Young, then Slayer," Grohl said. "It was all over the map, but what I got to appreciate was that music is such a beautiful art that you can't really judge it, you just have to let it ingratiate."

Anyway, check out their version of "War Pigs" and tell us what you think!