Back to the Future – celebrating its 35th birthday this year – is rightly regarded as one of the best time-travel movies ever made.

It has been spun off into theme park rides and a cartoon series, turned its lead (Michael J Fox) into a movie star, boasted a mega-hit theme song (Huey Lewis and the News' 'The Power of Love') and is even the inspiration for a stage musical.

But as the movie's writer/producer Bob Gale remembers, it could all have turned out very differently.

A race against time

As fans of the trilogy already know, Michael J Fox wasn't the original actor cast to play teenager Marty McFly, who travels from 1985 back to 1955 in a DeLorean time machine, disrupting the first meeting between his (future) parents.

Eric Stoltz, best known for roles in Mask and subsequently Pulp Fiction, was hired as Marty and filmed Back to the Future for five weeks in late 1984 before he was replaced. 

"Eric is a terrific dramatic actor, but as a naturally funny guy – not so much," Gale says. "Lea Thompson [who plays Marty's mother Lorraine] told us sometime later that she had a conversation with Eric on set and he felt that the movie was really supposed to be a tragedy.