In a candid revelation, Michael J. Fox has shed light on the dynamics behind the scenes of the iconic film Back to the Future, specifically the tensions stirred by his on-screen father. Fox’s latest memoir, Future Boy, delves into his experiences on the 1985 movie set, highlighting how co-star Crispin Glover, who portrayed George McFly, introduced a distinctive yet unpredictable energy that wasn’t always in sync with the production team’s expectations.

Fox reminisces about his prior acquaintance with Glover, noting that despite this familiarity, nothing prepared him for Glover’s unconventional approach to acting. He recalls, “Crispin never repeated a performance the same way twice,” emphasizing that Glover’s interpretation of George often diverged from the vision of director Robert Zemeckis and the crew.

In a lighthearted moment from his memoir, Fox quips, “Nobody puts Crispin in a box,” referencing the creative challenges Glover posed. This unpredictability led to practical solutions on set, such as the crew constructing a literal box to guide his movements.

Fox recounts a particular scene where Glover’s improvisational spirit caused him to stray from his designated position. “Crispin was supposed to follow a specific path between the clothesline and me,” Fox wrote. “Instead, he envisioned George as a wanderer, someone with a free spirit, who moved in unpredictable directions—often perpendicular to the camera.”

Fox shared that during one scene, Glover repeatedly wandered away from his mark. “As Crispin approached the camera, he was meant to stay in a lane between the clothesline and me. But Crispin had a different plan,” he wrote. “My guess is that he saw George as a wanderer, a free spirit who traveled in random patterns – in this case, perpendicular to the camera.”

Eventually, the crew came up with a creative fix. “They fabricated a miniature corral made of sandbags and C-stands, trapping Crispin into adhering to the parameters of the shot,” Fox said.

Despite the on-set challenges, Fox insists he “loved working” with Glover. “His talent was unquestionable, although his methods sometimes created friction,” he wrote. “Still, I respected how he remained true to George (as he understood and embodied him).”

Glover, who was just 21 at the time, did not return for the sequels Back to the Future Part II (1989) or Part III (1990); his role was recast with actor Jeffrey Weissman.

Fox also reflected on his dynamic with co-star Lea Thompson, admitting they didn’t immediately click after he replaced her friend Eric Stoltz in the lead role. “Probably not because I was friends with Eric Stoltz, who had just gotten fired,” Thompson said in a 2024 interview. Still, the two later developed a strong working relationship.

Beyond the nostalgia, Fox continues to speak candidly about his life with Parkinson’s disease, which he was diagnosed with at 29. “There are not many people who have had Parkinson’s for 35 years,” he told The Sunday Times. “I’d like to just not wake up one day. That’d be really cool. I don’t want it to be dramatic. I don’t want to trip over furniture, smash my head.”

In a separate interview with People, the Teen Wolf star described the day-to-day realities of living with the disease: “I wake up and get the message of what the day is gonna be like, and I try to adjust to it,” he said. “I keep getting new challenges physically, and I get through it.”