Brett Morgen, who directed the late singer's documentary "Kurt Cobain: Montage of Heck", revealed the big news during an interview with Bedford + Bowery, saying that the project would be released "this summer."
"The album of home recordings will feel like you're kind of hanging out with Kurt Cobain on a hot summer day in Olympia, Washington as he fiddles about. It's going to really surprise people," said Morgen.
"Just to be clear, it's not a Nirvana album, it's just Kurt and you're going to hear him do things you never expected to come out of him."
He said the cassettes included Cobain's records with wife Courtney Love, demo tapes and his covers of The Beatles' songs.