The Oscar-nominated filmmaker is in the final stages of completing a documentary focusing on Michael's landmark Bad album, celebrating the record's 25th anniversary, which will be shown later this year.
"We have footage in this documentary that no one's ever seen, stuff that Michael shot himself, behind-the-scenes stuff," he 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."
Besides Michael's artistry, Spike - who also plans to hold his annual birthday tribute to the star in Brooklyn, New York, on August 25 - said the documentary will show a more personal side of the late legend.
"He had a great sense of humour, and he was funny - so you'll see a lot of that stuff," he said.
"I'm more than just a huge fan of Michael Jackson, and having the chance to actually know him and work with him, I deeply care about his legacy. With this project I was able to uncover just what made this such a huge, important coming of age in his career and unearth compelling stories surrounding the making of the album, the long-awaited follow-up to Thriller, the short films and the tour that may have never seen the light of day."
"We really divided it into two: 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," he explained.