Last night at the 12-12-12 Concert, Sir Paul McCartney revealed a new song that made “Helter Skelter” sound about as tame as “I Wanna Hold Your Hand.” Has Macca dropped the classic pop standards of Kisses on the Bottom? We can only hope, as last night rocked.

Titled “Cut Me Some Slack,” the aforementioned song is the first (and realistically-speaking, probably the only) from his collaboration with Nirvana’s surviving members, Dave Grohl, Krist Novoselic and touring guitarist Pat Smear. The song will serve as the lead single from Grohl’s pride and joy, his upcoming Sound City documentary, so we can only assume a studio recording will eventually be released. The film is set for release at this January’s Sundance Film Festival.

McCartney’s introduction of the song was pretty priceless in a charmingly clueless sort of way: “The penny finally dropped, I realized I was in the middle of a Nirvana reunion.”

(Strange coincidence about this group of musicians: Darby Crash, singer of Pat Smear’s early band, The Germs, died just one day before John Lennon’s own death on December 8, 1980.)

Naturally, anything involving Nirvana wouldn’t be complete with a Courtney Love tirade. Cobain’s widow went non-nonsensical on the Facebook wall of Mark Yarm’s grunge book, Everybody Loves Our Town. She’s since deleted her comments, but here’s a screen-cap.

Thanks to McCartney and his classic rock brethren (plus Kanye, Chris Martin and more), the all-star 12-12-12 Concert raised millions upon millions of dollars to benefit Hurricane Sandy relief. Check out our full recap of the show, and head to iTunes to buy songs from the televised concert.

- Jillian Mapes, CBS Local