Last night on Saturday Night Live, Sir Paul McCartney and the surviving members of Nirvana performed their new track, “Cut Me Some Slack,” for the second time in four days.

The collective, which features McCartney, Dave Grohl, Krist Novoselic and Pat Smear (“Sirvana,” anyone?), originally debuted the song last Wednesday night at the 12.12.12 Concert for Sandy Relief at New York’s Madison Square Garden.

Fans of the heavy, raw-sounding tune with the strong “Helter Skelter” vibe will be happy to know that the studio version of the track is now available on iTunes at this location. You can hear it via the YouTube player below.

The song is part of Sound City — Real to Reel, the soundtrack album for Grohl’s highly anticipated documentary about Sound City, the famous California recording studio.

The film is set for a February premiere at the Sundance Film Festival. It also will become available through video-on-demand services as the Sundance projector starts rolling. The soundtrack album, which is available now for pre-order on iTunes, will be released March 12. Check out the full track listing below.

McCartney’s other Saturday Night Live contributions last night included a performance of “My Valentine,” with Joe Walsh on lead guitar, and “Wonderful Christmastime,” his 1979 Christmas tune, which featured a live children’s chorus. As he did Wednesday night, McCartney donned a slide and a Baratto cigar box guitar when performing “Cut Me Some Slack.”

Sound City — Real to Reel Tracklist:

01. Dave Grohl, Peter Hayes, and Robert Levon Been, “Heaven and All”
02. Brad Wilk, Chris Goss, Dave Grohl, and Tim Commerford, “Time Slowing Down”
03. Dave Grohl, Rami Jaffee, Stevie Nicks, and Taylor Hawkins, “You Can’t Fix This”
04. Dave Grohl, Nate Mendel, Pat Smear, Rick Springfield, and Taylor Hawkins, “The Man That Never Was”
05. Alain Johannes, Dave Grohl, Lee Ving, Pat Smear, and Taylor Hawkins, “Your Wife Is Calling”
06. Corey Taylor, Dave Grohl, Rick Nielsen, and Scott Reeder, “From Can to Can’t”
07. Alain Johannes, Chris Goss, Dave Grohl, and Joshua Homme, “Centipede”
08. Alain Johannes, Chris Goss, Dave Grohl, and Joshua Homme, “A Trick With No Sleeve”
09. 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”

Last night, as advertised, Paul McCartney was joined onstage at the 12-12-12 benefit concert by the surviving members of grunge giants Nirvana — Dave Grohl, Krist Novoselic and live guitarist Pat Smear.

Instead of Sir Paul leading the band through a medley of Bleach tunes, McCartney donned a slide and a cigar-box-style resonator guitar for a new song called “Cut Me Some Slack.” You can watch footage of the performance below.

“Recently some guys asked me to jam with them,” McCartney said, before being joined by Grohl and crew. “So I showed up like you do, ready to jam. And in the middle of it these guys kept saying, ‘We haven’t played together for years.’ Then it finally dropped… I finally understood I was in the middle of a Nirvana reunion.”

Grohl, Novoselic and Smear haven’t performed live together in more than 18 years.

Other performers last night included The Rolling Stones, The Who, Bruce Springsteen, Bon Jovi and Roger Waters, who was joined late in his set by Pearl Jam frontman Eddie Vedder, who contributed to a stirring rendition of the Pink Floyd classic, “Comfortably Numb.”

All of the proceeds from last night’s show will go to benefit the Robin Hood Relief Fund, which is still working to help the victims of Hurricane Sandy. For more information on how to donate, head here.