Activist and documentarian Michael Moore has proven a controversial figure throughout his career, wading into political conversations around big business, the insurance industry, and even war crimes, but now seems potentially primed to take on an even more scandalous subject: The growing legal conflict between “It Ends with Us” collaborators Blake Lively and Justin Baldoni.

“I’ve been working on something, yes, for the last number of months, but I can’t talk about that right now,” said Moore in a recent interview with Deadline. He later teased, “I’ll have some interesting stories to tell when I can speak about it, like what the heck Justin Baldoni, Wayfarer, and Blake Lively have to do with me trying to make a movie…”

The dispute between the star and her co-star and director began at the end of last year when Lively filed a complaint in the Los Angeles Superior Court...