Call it Maccavana, Sirvana, or, as the Sun hilariously did when the London tabloid broke the news, then unconfirmed, "Paul McKurtney." Whatever the name for Paul McCartney's collaboration with Nirvana's surviving members — the former Beatle has called it a "Nirvana reunion," and, hell, it's one-fourth of a Beatles reunion! — it's definitively no joke. "Cut Me Some Slack," the song McCartney, Dave Grohl, Krist Novoselic, and Pat Smear premiered for the world during the 12-12-12 concert for Hurricane Sandy relief, is now available as a similarly sludgy studio version. The improved fidelity brings out some sonic similarities to Soundgarden's latest, though of course McCartney's gorgeous yowls (and the band's backing harmonies) put this on a whole different map. Call it post-grunge power-pop? Whatever it is, McCartney and Grohl are having no trouble finding high-profile places to perform it. After first showcasing it at the charity event, the McCartney-led Nirvana incarnation also performed "Cut Me Some Slack" over the weekend on Saturday Night Live, where Sir Paul was the musical guest. An official video isn't online for whatever reason, but you can see a somewhat spammy-looking clip of their basically faithful performance below via the Audio Perv. McCartney also sang "Wonderful Christmastime," also not up on SNL's site, plus "My Valentine," from last year's Kisses on the Bottom. "Cut Me Some Slack" isn't the only all-star collaboration on Sound City's soundtrack album, titled Sound City - Real to Real. Stevie Nicks, Josh Homme, Trent Reznor, and many others are on the full trakc list, which you can check out below. Sound City - Real to Real track list: 1. Dave Grohl, Peter Hayes, and Robert Levon Been – "Heaven and All" 2. Brad Wilk, Chris Goss, Dave Grohl, and Tim Commerford – "Time Slowing Down" 3. Dave Grohl, Rami Jaffee, Stevie Nicks, and Taylor Hawkins – "You Can’t Fix This" 4. Dave Grohl, Nate Mendel, Pat Smear, Rick Springfield, and Taylor Hawkins – "The Man That Never Was" 4. Alain Johannes, Dave Grohl, Lee Ving, Pat Smear, and Taylor Hawkins – "Your Wife Is Calling" 6. Corey Taylor, Dave Grohl, Rick Nielsen, and Scott Reeder – "From Can to Can't" 7. Alain Johannes, Chris Goss, Dave Grohl, and Joshua Homme – "Centipede" 8. Alain Johannes, Chris Goss, Dave Grohl, and Joshua Homme – "A Trick With No Sleeve" 9. Paul McCartney, Dave Grohl, Krist Novoselic, and Pat Smear – "Cut Me Some Slack" 10. Dave Grohl, Jessy Greene, Jim Keltner, and Rami Jaffee – "Once Upon a Time… The End" 11. Dave Grohl, Joshua Homme, and Trent Reznor – "Mantra"