The 61-year-old made an appearance at Sundance Film Festival in Utah, during which he spoke about his career at large and his ongoing battle with Parkinson's disease.
Speaking about his relationship with Lloyd, who starred alongside him as time-traveling scientist Doc Brown, Fox declared his now 83-year-old scene partner "an enigmatic character".
But his mysterious nature meant Fox found it difficult to bond with Lloyd during the first two films of the 1980s trilogy.
"It took me a few films to get to know him," he told Variety Studio. "On 'Back to the Future Part III' we connected in a way we hadn't on the other films. I came to see how much he loved acting. I never got that before.
Watch: Michael J. Fox opens up about turning to alcohol to cope with Parkinson's disease diagnosis
"To sit down and talk about acting and talk about Shakespeare and 'King Lear'… This guy can play King Lear! People don't expect that of him. He's full of surprises."
"He can tell a movie's worth of story in two seconds and you get it," Fox continued. "Us regular actors have to lay out hours and hours to get the information out. Chris is brilliant at it.
"His love of film and his love of being an actor… He's not just a crazy guy, he's an artist."
Fox and Lloyd have since developed an unbreakable bond that has become as much beloved by fans as the Back To The Future franchise itself.
Over the past four decades since, Lloyd has been a fervent supporter of Fox's fundraising for Parkinson's disease, and appears alongside him at fan conventions for cast reunion specials.
An appearance at New York Comic-Con in October 2022 left fans "in tears" as they praised their long-standing workmanship and friendship.