After its initial debut on HBO, director Brett Morgan's documentary on the late Kurt Cobain, Montage Of Heck, has begun showing in select cities prior to it's wide-theatrical release. And, unlike the HBO version, the theatrical version features a previously unreleased solo song from the Nirvana frontman.

Stereogum originally captured the largely acoustic song, recorded in theater by a fan during the final credits. As previously mentioned, the song will be included on the soundtrack for the film, which will be released November 6th along with the film on DVD and Blu-Ray. The soundtrack will also featured numerous other unreleased material, according to SPIN.

Listen to the end credits song below, captured by a viewer in the stands.