Still, that’s an oversimplification of the process, which took about 500 artists and two years to perfect. When it comes to de-aging, visual-effects artists aim not to re-create or copy the image of an actor’s younger self, but to interpret the character being played. In Smith’s case, his clone in Gemini Man was trained as an assassin, so he couldn’t have the lanky build of Smith from The Fresh Prince of Bel-Air. On top of that, effects of this caliber require compromise: As much as dark lighting, long takes, and clever costuming help hide flaws in Junior’s presentation, the film couldn’t conceivably be told under such circumstances in every scene.

Lee admitted that the end result isn’t perfect—the final, daylight-drenched scene looked “goofy,” he told me—but the film operated “almost like a guinea pig” for the cutting-edge technology he wanted to implement. As a director, Lee often pushes filmmaking boundaries, so the idea of furthering de-aging by building a full digital human sounded appealing. “We are in a digital era,” he explained, “so to me it’s only logical to [de-age an actor] right in front of your eyes through digital effort.”

Indeed, de-aging actors digitally is becoming the new normal in Hollywood. Though the practice of manipulating an actor’s look rather than casting age-appropriate performers has been around since the mid-2000s—The Curious Case of Benjamin Button being a prime example—visual-effects artists have worked overtime on it this year. In March, the ’90s-set Captain Marvel toyed with Samuel L. Jackson’s appearance, erasing decades off his face. Marvel deployed the technique again in April, incorporating an estimated 200 aging and de-aging shots of various actors throughout Avengers: Endgame. Five months later, the horror sequel It Chapter Two de-aged its young cast members so that they would match their preteen looks from the first film. (Thanks, puberty!) And Martin Scorsese’s gangster epic The Irishman, released at the end of November, dialed back the ages of its stars, Robert De Niro, Al Pacino, and Joe Pesci—all in their 70s—to portray the lives of mobsters across entire lifetimes.

At a time when Hollywood’s population of box-office-busting movie stars is dwindling, de-aging allows existing ones to be reborn—or, at the very least, to ensure their longevity. For an industry that relies on rebooting franchises, it’s only logical that filmmakers would want to do the same to its bold-faced names. Consider the news that James Dean could be digitally resurrected to star in a new movie; taken to its bleakest, most Black Mirror–esque extreme, the notion of re-creating deceased actors via visual-effects has implications that could pave the way for a new era of moviemaking.

“It’s a form of immortality, if you think about it,” Olcun Tan, a visual-effects supervisor based in Los Angeles, told me. He pointed to Mickey Mouse as the optimal version of a “movie star” with staying power, a type of fictional character turned brand. To achieve everlasting fame, stars would go through the reverse, from being a household name to becoming a digitally reusable character, another tool in a filmmaker’s toolbox. “I’m not saying this is what the future will bring, because this is a little dark, but if you can imagine it, there is a likelihood it can happen,” Tan said. “Because if the film industry is trying to reverse current actor’s ages because it makes them money, you have to consider there is a likelihood they’ll license their appearance at some point, even after those people are gone.”