AN action movie project that has remained one of Hollywood’s most fabled unproduced films for over 20 years is getting another shot at the big screen.

Ang Lee, the celebrated filmmaker behind “Life of Pi” and “Crouching Tiger, Hidden Dragon,” is in negotiations to direct “Gemini Man,” the high-concept action thriller for Skydance.

The story centers on an aging assassin who tried to get out of the business but finds himself in the ultimate battle: fighting his own clone who is 25 years younger than him and at the peak of his abilities.

The project was first set up at Disney in 1997 as a pitch by Darren Lemke, with Don Murphy producing and Tony Scott directing. While always popular with execs, in and outside the studio, “Gemini” was considered unfilmable for many years. The producer and execs wanted to use computer effects to have the same actor play both parts but the technology to have one actor realistically carry that off for an entire movie did not exist.

That still didn’t stop development on it as writer after writer — including Brian Helgeland, Andrew Niccol and David Benioff — worked on drafts of the script. Benioff was paid a reported US$2 million for his work, showing exactly just how much the concept was loved.

Curtis Hanson was attached to direct at one point while Mel Gibson circled to star at another.

However, technological evolution took small steps. David Fincher aged and de-aged Brad Pitt in “The Curious Case of Benjamin Button.” “Tron: Legacy” did the same with Jeff Bridges.

Marvel in recent years has made it much more common with “Captain America: Civil War,” which featured a young Robert Downey Jr., young Michael Douglas in “Ant-Man,” and again in “Guardians of the Galaxy Vol. 2” with Kurt Russell. “Rogue One: A Star Wars Story” did it with Carrie Fisher and Peter Cushing.

But all these examples have been for short scenes, not for the duration of an entire movie, something that would strain budgetary and creative resources as well as believability.

“Looper,” directed by Rian Johnson, trod similar terrain as “Gemini,” using a time travel conceit rather than cloning, but used makeup to have Bruce Willis and Joseph Gordon-Levitt play the same character. (SD-Agencies)