The song features a rare falsetto performance from Kurt Cobain.

Perhaps the biggest news in the wake of Montage Of Heck came when an album of acoustic recordings from the Nirvana frontman was discovered. As the film moves closer to its theatrical release, director Brett Morgen revealed today in an interview with Billboard that one of the unreleased songs has been added to the film.

He noted that the untitled song was added without altering the film at all and described the untitled song as being reminiscent of the Beach Boys’ Brian Wilson, due to Cobain’s use of falsetto on it. The director has not said where the song is placed in the film because “I don’t want to get people out there bootlegging it on their cell phones”.

Montage Of Heck hits theaters August 7.