The Foo Fighters set the bar high for their weeklong residency on the ‘Late Show With David Letterman’ when, on their first night, they invited Zac Brown to the stage to cover Black Sabbath’s ‘War Pigs.’ Unsurprisingly, they exceeded all expectations on night No. 2 (Oct. 14) as Heart's Ann and Nancy Wilson joined them for a cover of 1977's 'Kick It Out' (written by lead vocalist Ann). Check out the Seattle-specific performance in the video above.

From the very opening monologue, the energy emanating from the crowd in the Ed Sullivan Theater was higher than we can ever remember; Letterman could hardly kick things off as he had to wait for the raucous applause to die down.

About 20 minutes into the show, the host was interrupted as the ‘FF’ signal lit up the sky behind him. Just as the Foos’ instantly recognizable logo appeared in the skyline -- harkening the Bat signal, for those who aren’t keeping up -- Dave Grohl and company ran out to the stage, answering the call. “That’s the Foo signal. It wasn’t me, I’m sorry,” Letterman told the boys. “They’re testing it. Nice job. I’m sorry.”

While last night’s show was stacked full of high-profile guests like New York Gov. Andrew Cuomo and Michael Keaton, the excitement only grew in anticipation of the Foos' performance. While Grohl stepped to the side to let the Heart women taken center-stage, that didn't diminish the absolute power and ferocity he and his crew displayed during the high-energy song.

Letterman wrapped up the show by saying what we were all thinking: “We should do this every night ... every night it’s a party, ladies and gentlemen.”

On tonight's (Oct. 15) appearance, the Foo Fighters will feature Tony Joe White -- a swamp rocker from Louisiana who wrote the '69 hit, 'Polk Salad Annie' -- as their special guest.

The Foo Fighters are gearing up for the debut of their eight-episode series on HBO, 'Sonic Highways,' this Friday, Oct. 17. A couple of weeks later, on Nov. 10, their latest full-length album of the same name will hit store shelves. Get details on the RCA Records album here.

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