Nirvana is part of Krist Novoselic's ''soul,'' and makes Dave Grohl feel like he's in the band again.
The Foo Fighters frontman feels his former bandmate still carries the "soul" of their previous group - which was brought to an end by the suicide of frontman Kurt Cobain in 1994 - and hanging out with him stirs up strong memories.
Dave told NME magazine: "He hasn't changed a bit, so to hear him speak or to hear him tell stories or to hear him talk about Nirvana - it really brings back The Feeling of being in the band because it's just part of his soul."
Dave also said the dynamic of the grunge band was created by the fine balance in drive and personality between Kurt and Krist.
He added: "You've got Krist, who was totally politically motivated, and then you've got Kurt, who was just such a brilliant artist, that it was that weird conflict or dichotomy or whatever it is.
"Those two things shouldn't really co-exist in a way, so whenever something's released, usually to me it's only authentic if it comes from Krist Novoselic."
Dave and Krist recently worked together on the track 'I Should Have Known' from the Foo Fighters' latest album 'Wasting Light,' and also on the 20th anniversary reissue of Nirvana's classic 'Nevermind' album.