Could Paul McCartney be standing in for the late Kurt Cobain for a Nirvana reunion tonight?

That's what the U.K. tabloid The Sun is reporting, claiming that McCartney suggested to Dave Grohl that they get together and “just make something up” for the 12-12-12 Sandy benefit tonight at New York's Madison Square Garden. The Sun says Grohl suggested they jam with some of his friends and that McCartney found himself playing with Grohl on drums, Krist Novoselic on bass and Nirvana touring guitarist (and Foo Fighters guitarist) Pat Smear.

The paper quotes McCartney as saying, "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.”

Whether this report is true won't be known until McCartney closes the show tonight. We can confirm that Grohl is playing one song tonight with McCartney, but we don't know who else will be performing with them. And this wouldn't be the first time Grohl, Novoselic and Smear have played together since the days of Nirvana -- Novoselic joined Foo Fighters on stage at two shows back in 2011.