“Chris is a great guy. He’s very enigmatic,” Fox said. “It took me a few films to get to know him. On ‘Back to the Future Part III’ we connected in a way we hadn’t on the other films. I came to see how much he loved acting. I never got that before. To sit down and talk about acting and talk about Shakespeare and ‘King Lear’… This guy can play King Lear! People don’t expect that of him. He’s full of surprises.

The “Back to the Future” star earned a big standing ovation at Sundance after the world premiere of his new documentary Still.

Directed by Davis Guggenheim, the documentary explores the intersection of Fox’s legendary career and Fox’s life with Parkinson’s disease. The film is already backed by Apple. Fox was diagnosed with Parkinson’s disease in the 1990s.

“I didn’t want to make a Parkinson’s movie. I don’t want to make a sick movie. I want to make a movie about a life,” Guggenheim said.  “The one thing he said to me was, ‘No violence.’ We hope the tone of the movie is not pitying. This is a movie about a wild life, an incredible ride of ups and downs and a Hollywood 1980s movie star and what happens when life throws him a curveball.”

Fox joined Back to the Future after production was already underway, with Lloyd having filmed scenes with original Marty McFly actor Eric Stoltz. Director Robert Zemeckis came to realize that Stoltz wasn’t right for the part, so Fox was cast and the production had to reshoot scenes.