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Back to the Future zoomed into movie theaters for the first time on this day in 1985 to the delight of audiences everywhere, and now we're using our special ET "Video Time Machine" to travel back to '85 -- and our first interviews with co-stars Michael J. Fox and Lea Thompson about the movie!

Video: Michael J. Fox Reminisces at 'Back to the Future' Reunion

Just a month after the Robert Zemeckis-directed/Steven Spielberg-produced movie opened to blockbuster business, ET revisited Fox, who talked candidly about how he felt about replacing Eric Stoltz in the lead role of the film.

"[Zemeckis and others] talked to me a little bit about why there were creative differences and what not, and their compassion and their feeling for what Eric was going to think and how Eric was going to feel impressed me," said Fox, who was pulling double duty on his hit sitcom Family Ties while shooting Back to the Future. "But there was so little time to really think a lot about getting nervous about replacing another actor ... it was just like, 'I've got to be there Tuesday,' and boom, I was there and doing it. And then it was just staying awake."

We also spoke with Fox three months before the movie opened, and he shared details about the "magical" quality of the film and his near-future aspirations.

"I hope that if Back to the Future does real well that it will open up an opportunity for me to do another film on my next hiatus," said Fox. "Things are just so good right now, and so much fun, that I don't want to waste any of this time worrying about tomorrow."

Pics: 'Back to the Future' and Top Time Travel Movies

A year after Back to the Future became a huge hit, Lea Thompson also became a hot commodity, and ET asked her to compare her role in the film to her other roles in Space Camp and the now-infamous Howard the Duck.

Watch the video and enjoy!