Spike Lee is working on a documentary on Michael Jackson, which will be comprised of footage from the recording of his iconic 'Bad' album.

Although Lee had been friends with the King of Pop for years, he said that he learned new things about the star while sifting through the footage, calling it a "treasure chest of findings," The Hollywood Reporter reports.

"We have footage in this documentary that no one's ever seen, stuff that Michael shot himself, behind-the-scenes stuff," Lee said. "We had complete access to the vaults of Michael Jackson ... He wrote 60 demos for the Bad record. Only 11 made it. So we got to hear a lot of that stuff, too, so it was just a great experience."

The director added that fans will see the "funny" side of Jackson, while also hearing from artists like Kanye West, Mariah Carey and Sheryl Crow, all of whom contribute interviews for the film.

"We really divided it into two things: Artists today who were influenced by Michael, and then people who worked side by side -- musicians, songwriters, technicians, engineers, people at the label, who were all committed to Michael, to the follow-up to the biggest record of all time, which still is 'Thriller.'"

The as-yet-untitled documentary will be released later this year, honoring the 25th anniversary of 'Bad.' The LP is being re-released on Sept.18 with additional tracks, a DVD and other extras.

Watch the Michael Jackson 'Bad' Video