MUMBAI: HBO's forthcoming Kurt Cobain documentary 'Montage of Heck' will feature an unreleased 12-minute acoustic song featuring the late Nirvana frontman. News regarding the unheard track was hinted at a few months ago, but was confirmed recently, when director of the documentary Brett Morgen tweeted, "Listening to a mind blowing 12 minute acoustic Cobain unheard track that will be heard on the montage of heck soundtrack."

Listening to a mind blowing 12 minute acoustic Cobain unheard track that will be heard on the montage of heck soundtrack. Hello @truefalse— Brett Morgen (@brettmorgen) March 7, 015

The documentary is supposed to be the first fully-authorised documentary about the iconic grunge rock musician. The official synopsis, as stated in the HBO release that the network issued a few months ago, says “The film provides no-holds-barred access to Cobain’s archives, home to his never-before-seen home movies, recordings, artwork, photography, journals, demos, personal archives and songbooks.”The film is also said to include an unreleased Beatles cover. ‘Montage of Heck’ is executive produced by Cobain’s daughter, Frances Bean Cobain. The film's title, Montage of Heck, takes its name from a musical collage that was created by Cobain with a cassette recorder with four tracks in about 1988, of which there are two versions: one is about thirty-six minutes long and the other about eight minutes long.‘Montage of Heck’ will have a limited theatrical run in the US, before premiering on HBO on 4 May.Meanwhile, TMZ recently reported that Cobain's widow Courtney Love has asked her lawyers to go after whoever posted ‘Flacid Bone,’ an unreleased Nirvana song that was allegedly stolen from Love through a computer hack. The released track however, is a fake.