AMSTERDAM, NETHERLANDS - 25th NOVEMBER: Kurt Cobain from American rock band Nirvana performs live on stage at Paradiso in Ams
Peter Pakvis/Redferns

Here's an album we didn't anticipate to ever hearing: A solo record by Kurt Cobain will be unleashed this fall.

To coincide with the physical release of HBO's Emmy-nominated documentary Montage of Heck, the film's director Brett Morgen put together a companion soundtrack of unreleased music from the Nirvana singer. Morgen told Billboard that the album contains all of the music featured in the film, a dozen additional tracks, "audio montages" and even a "sketch comedy routine." 

The director said he found "hours upon hours of never-before-heard Cobain music" while researching and pulling content for the doc that included more than 200 hours of recordings on 107 unmarked cassette tapes left behind by the late icon. 

Despite being a leader in bringing grunge to the mainstream, Cobain's demo material ranges "from thrash to ragtime and everything in between," Morgen said. In addition to revealing the music, it paints "a lighter portrait of Kurt than one might expect," he added: 

"You really get a sense of how happy he was simply by creating himself. His lyrics are really playful, and, at times, you can feel his smile and warmth coming through...these are all just Kurt by himself with the guitar. These aren't multi-track, finished songs or work-ups, but they're extraordinary. I think they provide a tremendous insight into his [creative] process. I think they further our understanding of Kurt, both as a musician and as a man."

Morgen says the as-yet-untitled LP will arrive on November 6 via Universal Music Group, the same day as the film's DVD and Blu-ray release.