Watch the First Moments Michael J. Fox Stepped Into the Role of Marty McFly in ‘Back to the Future’

Hard to believe that Back to the Future just turned 40 years old. Robert Zemeckis and Bob Gale’s iconic time-travel Amblin film starring Michael J. Fox and Christopher Lloyd introduced the world to a beloved duo, and it’s really hard to imagine anyone else in the roles of Marty McFly and Doc Brown. But as the lore goes, Fox was not originally Marty; he notoriously took over the role from Eric Stoltz, who was just not working out in the role opposite Zemeckis’s ensemble.

In an exclusive clip that Universal Home Entertainment has shared with io9, writer Bob Gale talked about the first night Michael J. Fox took over the role and how it immediately changed the vibe of the shoot for the better.

“The first movie, my absolute favorite moment, there’s no question about it, was the first night that Michael J. Fox came to work. We just fired our lead actor. Some members of the crew thought we were out of our minds. Nobody ever fired their leading man five and a half weeks into shooting,” he shared, as seen in the clip below over some of the first footage that Fox appeared in. You can also see the actor talk about going from the daytime Family Ties shoot, the hit television show he starred in, to the Back to the Future set at night.

“Michael comes bounding on his set, starts performing the scene with Christopher,” Gale said of the instant chemistry that would go on to make Marty and Doc so endeared to generations of sci-fi fans. “And it’s gold. I mean, it’s just the best. This giant weight went away, like, yeah. This kid is Marty McFly.”

And the rest, as they say, is pop culture history. Fox and Lloyd would go on to star in the franchise sequels, making the Back to the Future films one of the most treasured sci-fi series of all time.

Back to the Future 40th Anniversary Edition is out now in 4K on digital platforms.

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