Paul McCartney & Nirvana? Beatle Joining Remaining Members at Concert for Sandy

Paul McCartney might assume the position of Nirvana's Kurt Cobain tonight. The Beatles legend is rumored to be performing with the grunge group's surviving members Dave Grohl and Krist Novoselic at New York's Madison Square Garden as part of the 12-12-12 Concert for Sandy Relief.

The Guardian reports the trio (and Pat Smear, who toured with Nirvana) will play a new song tonight after secretly working together in a studio. The collaboration came about when Grohl recently asked McCartney to "jam with some mates" according to a spokesman.

Click Here to Watch the 12-12-12 Concert for Sandy
"I didn't really know who they were," McCartney said of Novoselic and Smear. "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."

Officially, the meeting of rock titans remains unconfirmed, with PR reps for McCartney and Grohl telling SPIN magazine "we can neither confirm nor deny" the reports. There's also no word that the performance will contain a Nirvana song, a Beatles tune or entirely new material.

After Cobain committed suicide in 1994, Grohl went on to form Foo Fighters. He's also had success with stints in Queens of the Stone Age and Them Crooked Vultures, the latter of which included Queens of the Stone Age singer Josh Homme and Led Zeppelin bassist John Paul Jones.

Elsewhere, Backstreets -- an authoritative site devoted to Bruce Springsteen -- states that Springsteen and the E Street Band will open tonight's concert at 7:30PM ET. Pearl Jam's Eddie Vedder will also join Roger Waters onstage during his performance.

Other acts slated to perform include Bon Jovi, Eric Clapton, Billy Joel, Alicia Keys, Chris Martin, the Rolling Stones, Kanye West and the Who. According to the concert's website, the benefit gig will be broadcast to more than two billion people around the world. Proceeds will go to the Robin Hood Foundation to assist those devastated by the massive storm and resulting flooding.

UPDATE: Novoselic says it's a new song (and also tweets at the Pope, for some reason).

It is a new song that's kind of Helter Skelter meets Scentless Apprentice. It rocks with a heavy groove. St. Paul is powerful. @pontifex

- Krist Novoselic (@KristNovoselic) December 12, 2012