Turns out Marty McFly was one busy guy!
Opening up to Parade, Michael J. Fox, 50, describes having to juggle his Family Ties and Back to the Future duties in the mid-80s.
"I came back from Christmas break and I went to work on Family Ties...that night [for Back to the Future] I was standing in the parking lot with flaming tire tracks running between my legs, and my whole world changed," Fox tells the site.
For the next few months, "I ended up getting about three hours of sleep a night, because they had to get the movie out that summer," the Golden Globe winner reveals. "[While we were making it], I thought I sucked in it. I really, truly thought I was terrible. So many times I was practically unconscious because I was so tired."
A panicky Fox was ready to apologize to his management when he heard his agent had attended a screening of the movie in L.A. "[He] called me in London, where I was doing Family Ties Vacation. He said, 'I just saw the movie.' I said, 'I'm sorry, I'll do better next time.' And he said, 'No, you don't understand. This is going to be the biggest movie of the summer.'"
Despite the actor's insecurities, his agent's prediction turned out to be right; the flick (which also starred Christopher Lloyd and Lea Thompson, and helped launch Fox to superstardom) grossed almost $351 million worldwide, and went on to become one of the most beloved sci-fi films of all time.