The documentary Kurt Cobain: Montage of Heck will play on HBO in a couple weeks, but you can hear one of the previously unreleased songs from it right now. And it's an interesting one: a stripped-down cover of the Beatles' 'And I Love Her.'

You can listen to the song -- which comes from an old cassette made by Cobain and runs for less than two minutes -- above.

The movie tells Cobain's story through a series of interviews, artifacts and unheard songs and snippets that he recorded at home and on cassettes over the years. While the film touches on Nirvana's success, and Cobain's struggles with it until his suicide in April 1994, much of it focuses on the singer, songwriter and guitarist's personal life.

The 'And I Love Her' cover certainly reflects this, revealing a side of Cobain his fans rarely saw. It retains the Beatles' spare arrangement from their Top 15 1964 hit, with Cobain accompanying himself on guitar as he sings in a quiet, plaintive tone, not the raging, throat-shredding howl that made him famous on songs "Smells Like Teen Spirit" and "In Bloom."

Kurt Cobain Montage of Heck promises other unheard Cobain and Nirvana music, most of it likely featuring the same sketchy home-cassette fidelity heard on 'And I Love Her.' The film will also screen briefly in theaters before its HBO dates next month.

See Nirvana and Other Rockers in the Top 100 Albums of the '90s

Rock's Tragic 27 Club

More From Ultimate Classic Rock