Watch Paul McCartney & Nirvana Play New Song

It's not a "Come As You Are" cover after all (thank God), but a new song called "Cut Me Some Slack".

Johnny Firecloudby Johnny Firecloud

Former Beatle Paul McCartney joined the surviving members of Nirvana for a hugely anticipated collaboration performance at the 12.12.12 concert at Madison Square Garden on Wednesday – but it wasn't an ill-conceived run through "Smells Like Teen Spirit" that fans were witness to. 

Nearly six hours into the star-studded benefit concert (which in itself was packed with stellar performances), former Nirvana members Dave Grohl, Krist Novoselic and Pat Smear joined McCartney onstage to debut the brand new song "Cut Me Some Slack," and damned if this song isn't badass:

Just after the song’s debut, a website was set up to clear the air on just where "Cut Me Some Slack" came from: it was actually recorded for Grohl’s upcoming Sound City documentary and its accompanying soundtrack album, titled Sound City – Real to Reel.