The studio version of "Cut Me Some Slack," the song debuted by Paul McCartney and the surviving members of Nirvana last Wednesday night (December 12th) at the 12-12-12 benefit concert in New York, has been released on iTunes. The surprise collaboration was recorded for Nirvana drummer/Foo Fighters frontman Dave Grohl's upcoming documentary Sound City, which will premiere at the Sundance Film Festival in January before rolling out via Blu-ray, DVD and VOD on February 1st.

• The raw-sounding track comes across as heavier than what one might expect to hear from McCartney, but Grohl told us a while back that Nirvana liked to rock as hard as any other band: ["There was a lot of that crazy, heavy element in Nirvana. You know, the one thing that Nirvana was against was just the bulls**t."]
  
• McCartney, Grohl, Nirvana bassist Krist Novoselic and Nirvana/Foo Fighters guitarist Pat Smear premiered the song live during the all-star charity concert, which was organized to raise money for the victims of Hurricane Sandy.
• Grohl, Novoselic and Smear have not performed together onstage since the last Nirvana tour in 1994, before the death of band leader Kurt Cobain.
• The former Beatle said he had no idea that he was jamming with three-quarters of Nirvana during the recording session, explaining, "I didn't really know who they were. They are saying how good it is to be back together. I said, 'Whoa? You guys haven't played together for all that time?' And somebody whispered to me, 'That's Nirvana. You're Kurt.' I couldn't believe it."
• The soundtrack to the documentary, which chronicles the history of a legendary Los Angeles recording studio, will be released on March 12th.
• The 11-song soundtrack contains a number of blockbuster collaborations involving Grohl, the other members of Foo Fighters, Stevie Nicks, Trent Reznor, Josh Homme, Rick Springfield, Corey Taylor and more.