Paul McCartney to front a reunited Nirvana? How's this for rock history in the making? Paul McCartney is expected to front a Nirvana reunion tonight, according to a flurry of online reports. McCartney will reportedly step in for late frontman Kurt Cobain as surviving members of the pioneering grunge band reunite for Wednesday night's Sandy relief concert at New York's Madison Square Garden. The 70-year-old Beatles icon is said to have been secretly working with Foo Fighters singer Dave Grohl and bassist Krist Novoselic following a recent studio session, according to The Sun. Cobain and Novoselic formed Nirvana in the late 1980s, with Grohl joining as drummer in 1990. Cobain committed suicide in 1994. McCartney's New York-based publicity firm Nasty Little Man, which also represents Grohl, declined to comment on the report. "We can neither confirm nor deny," one of the agency's representatives said via email. This wouldn't be the first time McCartney has jammed with the Nirvana drummer. In February, Grohl joined Sir Paul to close out the Grammy Awards show with "Golden Slumbers," "Carry That Weight" and "The End" - a trio of songs that make up the end of the Beatles album "Abbey Road." Will McCartney return the favor and sing lead on "Stay Away," "On A Plain" and "Something in the Way," the three songs that conclude Nirvana's "Nevermind"? That seems unlikely, but don't rule out another all-star combo of artists. After all, that Grammy performance also featured Bruce Springsteen, another artist performing tonight. There are also rumors that the McCartney-fronted Nirvana could debut a new song. Billed as "12-12-12: The Concert for Sandy Relief," the event is crammed with a heavyweight lineup of marquee acts including the Rolling Stones, Bruce Springsteen & The E Street Band, Kanye West, Alicia Keys, the Who, Roger Waters, Eddie Vedder, Bon Jovi, Billy Joel and Eric Clapton. The concert could be one of the most-watched music events in history with more than 2 billion people having access through TV broadcasts and online streaming. Movie theaters in New York, New Jersey and Connecticut will also screen the special. Proceeds are to go to the Robin Hood Foundation to provide disaster relief in the wake of Superstorm Sandy.