This may look like an odd sentence, but a new Nirvana song has just been released. As a part of Nirvana's 'In Utero: 20th Anniversary Edition' (out today), a ton of rare recordings and footage has been unveiled, but the Nirvana track 'Forgotten Tune' is the only piece of the re-release that is truly never-before-heard.

The rock world is buzzing about the 'In Utero' special edition reissue as rabid Nirvana fans, who can never get enough of the band, are currently raiding music stores. Along with the original track listing from 'In Utero,' the new piece of Nirvana history features bonus tracks, b-sides, unreleased alternative mixes, 2013 remixes and demos … and that's just the audio portion.

Among the 43 tracks housed within the new 'In Utero' release, 'Forgotten Tune' delivers a new Nirvana jam from one of the band's rehearsal sessions. Raw and purely instrumental, 'Forgotten Tune' is simple, but will give Nirvana fanatics something fresh to gnaw on for some time.

"'Forgotten Tune,' we found it and were like, what is this song? And I don't really remember," Nirvana bassist Krist Novoselic tells NPR. "And [we were], like, what do you want to call it? And I'm like, I don't want to give it a name, so let's just call it 'Forgotten Tune' and let people make up their own minds what it is."

Nirvana's iconic 1993 'Live and Loud' performance on MTV is now available as a part of the 'In Utero' deluxe re-release as well as a standalone DVD. The repackaged 'Live and Loud' concert is now, for the first time ever, presented in full along with unearthed rehearsal footage.

Check out Nirvana's unheard jam 'Forgotten Tune' above along with rehearsal footage of 'Radio Friendly Unit Shifter' and 'Very Ape' in the videos below! To grab your own copy of Nirvana's 'In Utero: 20th Anniversary Edition,' click here.

Nirvana, 'Radio Friendly Unit Shifter' (Rehearsal)

Nirvana, 'Very Ape' (Rehearsal)