Spike Lee at the premiere of the film "Red Hook Summer" at the 2012 Sundance Film Festival in Park City, Utah. /AP

Film director Spike Lee is working on a Michael Jackson documentary to celebrate the 25th anniversary of the late pop icon's "Bad" album.

"We had complete access to the vaults of Michael Jackson," Lee told Billboard. "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."

Lee added that the documentary will include footage that Michael Jackson shot himself and other behind-the-scenes material that no one has ever seen. Lee promises that fans will see a more personal side of Jackson.