By Shannon Carlin, Radio.com

The Foo Fighters kicked off their week-long residency at The Late Show with David Letterman by wearing their metal heart on their sleeves.

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Dave Grohl and the band did their own version of Black Sabbath’s 1970 classic “War Pigs” with a little help from Zac Brown, who added a little southern twang to the track. Not to mention that Brown came out wearing a very festive hat. Watch out Pharrell.

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When it was all said and done David Letterman seemed pretty excited about the performance saying this combination of Sabbath, Brown and the Foo Fighters was as good as it gets, “What do you want from me, kids?”

Letterman forgot to mention that he interviewed Grohl about their upcoming HBO series Foo Fighters: Sonic Highways, which takes fans into the recording of the album in eight cities across America and premieres this Friday (Oct. 17).

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