They are very few people on this planet cooler than Dave Grohl, but one who definitely fits the bill is Joan Jett, whose coolness is off the meter.

As fans of both acts know, Jett joined the Foo Fighters a few days ago at New York's Madison Square Garden for a blazing version of Jett’s punk classic, “Bad Reputation.” It’s fun to watch Pat Smear and Grohl bouncing around, obviously having the time of their lives, as Jett tears the roof off MSG.  Grohl, who notes it's the first time they've performed together, appropriately introduces her as “the baddest motherfucker I know”  and calls it the "greatest fucking night of the tour." I'm convinced that if you look up "true believer" in the rock and roll dictionary, there would be a picture of Jett, who wrote this song with her longtime manager Kenny Laguna, Ritchie Cordell and Marty Joe Kupersmith more than (gasp) 30 years ago.

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If you missed that magic, Jett and the Foos are performing “Bad Reputation” on  “The Late Show with David Letterman” tonight.  This time, there’s no excuse.