Credit: Jeff Kravitz/FilmMagic

An unreleased acoustic Kurt Cobain track will be featured on the soundtrack to the HBO documentary about the late rocker, Kurt Cobain: Montage of Heck, the film’s director Brett Morgen recently announced via Twitter.

The “mind-blowing” 12-minute song is part of the score that includes all unreleased Cobain music, Morgen told Rolling Stone at Sundance Film Festival in January, where the film premiered with rave reviews.

While Kurt Cobain: Montage of Heck is set for its television debut on May 4, no further details have been released regarding the film’s soundtrack.