Christopher Lloyd, the actor best known for Doc Brown from the Back to the Future series, has revealed what he would like to see in a hypothetical Back to the Future IV.

Though creator/director Robert Zemeckis remains opposed to returning for the further adventures of Doc and Marty McFly, fans and the actors have all expressed interest in just that over the years. And so, when asked about his ideas on what he'd like to see in a theoretical fourth film to the franchise, Llyod was happy to share his ideas with the Niagara Falls Comic Con audience.

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"I think somehow it needs to kind of convey a message about something that’s important to everyone, universally, like climate change," the actor opined. "Some way of incorporating whatever fever is going on at the moment into the film and keep the feeling of one, two and three... That’s a tricky, tricky deal. Because you don’t want to do another one and disappoint. So I don’t know. I’d be happy to, for myself. But we’ll see.”

Along with talking about some of his other projects, like Star Trek III, Clue, and Taxi, one fan asked Llyod about his experience working with his fellow Back to the Future Co-Star, Micheal J. Fox. Llyod called him "easy to work with."

“He was who he was, I was who I am, and there was never any awkward anything," Lloyd recalled. "We just knew how to be our characters with each other, and it was very comfortable,” he said. “He has a great sense of humor and intelligence.... He's just so present."

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While there have been a lot of remakes, reboots and additional installments to franchises to a number of beloved '80s film series, Back to the Future remains one of the few not to have a sequel set years later, or a remake/reboot of sorts. The closest fans ever got to a new entry in the franchise has been through 2010's Back to the Future game by the now-defunct Telltale Games, which featured Llyod reprising his role as Doc Brown, and IDW Publishing's comics, some of which were scripted by the movie's screenwriter, Bob Gale.