'Unreleased' Kurt Cobain songs to feature in new HBO documentary

Previously unheard Kurt Cobain songs will soon feature in a new documentary by HBO about the singer and songwriter of Nirvana, who died 21 years ago.

The film 'Kurt Cobain: Montage Of Heck' was already known to include home movies, recordings, artwork and extracts from Cobain's journals, songbooks and archives, Stuff.co.nz reported.

The documentary will be directed by Brett Morgen, who had said in a press release that when he started the project eight years ago he assumed there was little "fresh material" to unearth, but once he stepped in the singer's archive, he discovered over 200 hours of unreleased music and audio, a vast array of art projects (oil paintings, sculptures).

He said that he also discovered countless hours of never-before-seen home movies, and over 4000 pages of writings that together help paint an intimate portrait of an artist who rarely revealed himself to the media.

The documentary is expected to screen in May, a month after the 21st anniversary of Cobain's death.