Michael J. Fox is recalling the time in his career when he booked the two roles that many know him for now.
In his new book, "Future Boy," Fox tells the story about when he starred in the television sitcom "Family Ties" and the blockbuster film "Back to the Future" at the same time.
"It was an amazing time," Fox told "Good Morning America" co-host George Stephanopoulos.
Fox's three-month journey of starring in both projects almost didn't happen because the creator of "Family Ties" didn't want to risk losing Fox, who starred as Alex P. Keaton on the hit TV show.
At the time, actor Eric Stoltz was cast as the iconic role of Marty McFly, but director Steven Spielberg wanted Fox as the lead in his film, which would go on to become a trilogy.
"They were shooting with another actor and it hadn't been what they wanted it to be," Fox said. "So they were coming at me again and he (the "Family Ties" creator) said, 'I'm gonna let you do it, but you're gonna have to do the show in the daytime, the movie at night. And I don't want to hear about the movie."
Fox added that he was told that the show's creator didn't want Fox to make up any excuses either, if he couldn't handle juggling both jobs.
Nevertheless, the "Family Ties" creator said, "Read the script and if you think it's okay with the script, you should."
"It was in my hand," Fox said and recalled that the show creator said the script was "the best script I ever read."
For Fox, that was enough to convince him to take on the role of Marty.
"I was completely doin' it," he said.
By day, Fox worked on the set of "Family Ties," and by night, he would film "Back to the Future."
He recalled the Teamsters picking him up for both gigs, him changing wardrobes and then going to bed at 3 or 4 a.m. He'd wake up to do it all over again.
Fox said, "When they come, they turn on the shower, make a pot of coffee, get me outta bed. I'd go and have the coffee in the shower and then I'd be at work again."
The actor added that there were times on the set of "Family Ties" when it would be what he described as a "blur."
"I just -- got into shark mode and just kinda was (moving) around and given' the scene," he began. "It was just this blur and there were some funny things (that) happened. One time I was on 'Family Ties' and so I went to get my camcorder. And I was gonna have my camcorder, I was really freakin' out because I -- my cue was coming and I said I didn't have a camcorder."
He continued, "And at the last minute, I realized I don't have the camcorder. Marty has the camcorder. Alex has the briefcase. So I mixed up the props. I was looking for Marty's props, not Alex's."
Looking back on "Back to the Future," Fox said that the "Johnny B. Goode" scene in the film, when Marty McFly takes the stage during his parents' prom night.
Fox, who knew how to play the guitar, told filmmakers that he would "master the track note for note" so it looked realistic on screen.
He told them, "If you don't shoot my hands, it's just fake."
While he says some audiences argued that the scene didn't need to be in the film, Fox said it was important to Marty's character.
"Marty was a guy who thinks he's not gonna make it," he said. "No one will buy into this dream. Never gets a chance to really reach people and to reach an audience and be the musician he wants to be."
When it comes to the film's message, Fox thinks it's one that many can relate to.
"It's about bullies," he said. "It's about standing up to bullies. We live in a really bully culture right now. And I think there's something about that. There's something about seeing the little guy stick up to bullies that people love."
He added, "I think there's also something about time and about family and about what we mean to each other."
Fox said that it's "amazing" to see what "Back to the Future" means for others.
He added that when he meets fans who share their stories with him and how much the film means to them, he says it's his chance "to give people something."
"They're giving me something," he said. "They're giving me something for 30, 40 years. They've given me my life. They've given me my joy in the work that I do and I'm forever grateful to people for that."
"Future Boy" will be available on Oct. 14 and is available now for preorder wherever books are sold.
