According to The Pulse Of Radio, former NIRVANA bassist Krist Novoselic spoke with the Hivecast about recently collaborating again with FOO FIGHTERS frontman Dave Grohl, who also played drums in NIRVANA. Novoselic kept the details to a minimum, only admitting that it was for the "Sound City" documentary that Grohl is making. He explained, "You've got to ask Dave what we did though because he told me not to tell anybody. It's around the 'Sound City' documentary. I went to Pasadena to go see Ben [Shepherd] and Kim [Thayil], because they were in L.A. making a video for [SOUNDGARDEN's 'Avengers' single] 'Live To Rise'. And so like we went to this hotel room, and we were like having some beers, and like they were playing their new song and I was playing our new song. It was kind of like the old days, like, 'Wow, we haven't done this in 20 years.'"

The documentary, which Grohl is directing, is about the legendary Sound City recording studio in Los Angeles, where acts ranging from FLEETWOOD MAC to METALLICA to Tom Petty to NIRVANA recorded many classic rock albums.

Grohl purchased the studio's main mixing board after the facility closed its doors a few years back.

The film, which Grohl reportedly hopes to premiere this fall, will feature new musical collaborations between a number of different artists.

Novoselic, who has kept a relatively low profile since NIRVANA ended in 1994, contributed bass and accordion to the track "I Should Have Known" from FOO FIGHTERS' most recent album, "Wasting Light".

It was the first time that Novoselic and Grohl had recorded together in nearly 20 years.