In the action thriller, which had its Hollywood premiere on October 6, Smith plays Henry Brogan, an elite assassin who finds himself pursued by a younger clone of himself, known as Junior.
Actor Will Smith said it was 'a little freaky' to see a digitally-generated 23-year-old version of himself on screen in the clone movie 'Gemini Man'.
In the action thriller, which had its Hollywood premiere on Sunday (October 6), Smith plays Henry Brogan, an elite assassin who finds himself pursued by a younger clone of himself, known as Junior.
"It's really different, it's not de-ageing, right, so it's not my face and they just made it look younger, it's a 100 per cent digital character. It's the first-ever 100% digital human," Smith said on the red carpet.
Oscar-winning director Ang Lee and special-effects technicians at Weta Digital production house built the virtual version of Smith using special cameras and drawing on old footage of the actor as a young man.
Lee pushed the technical boundaries even further by shooting the movie at 120 frames per second - five times faster than a regular movie, giving clarity and detail to the film.
"We're in a digital era. A lot of new possibilities. And, of course, at the end of the day, you tell human stories and you entertain people. That hasn't changed. But the new tools are quite incredible. I think it might change our perception of movies because you're more inside of it," Lee said.
Actor Benedict Wong described the process of acting alongside the younger version of Smith, joking that the digital character was 'a right diva'.
"We had Victor, who was Will's body double, who'd shoot that scene and then we would go into the studio with the Weta cameras and we'd look at the performance, how we'd shot and then Will would then switch into the young Will and then we would replicate our movements, yeah. Will Smith in a leotard, I can't unsee that now," he said.
'Gemini Man' opens in theatres in the U.S. on October 11.