Will Smith says working with digital double in Gemini Man raised philosophical questions

With his name twice across the top of the film's poster, it is no spoiler alert to say that the main attraction of Gemini Man is star Will Smith's dual role - that of protagonist Henry Brogan and his digital double and antagonist code-named Junior.

In the Lee Ang-directed action thriller, which opens here tomorrow, Brogan is an ageing government hitman who is retiring after his last assignment.

But a paramilitary billionaire tycoon (Clive Owen) has created a clone of Brogan by stealing his DNA 25 years earlier when they were army colleagues.

Junior, a 23-year-old version of Brogan, is then programmed to take out the assassin who knows too much.

At our interview at the Four Seasons hotel in Budapest, where part of the film was shot, Smith spoke about how he reacted when he first saw his doppelganger.

The 51-year-old US actor said: "My heart jumped the first time I saw that imagery. It is really chilling and weird to see your digital reincarnation in that way."

But ever the comedian, he continued: "But now there is a 23-year-old digital version of myself, it is an avatar that exists, so I can use it for other films. And as it gets better and better, can a young Will Smith make a movie with a young Marlon Brando?"

He goes on to explain the digital process.

"They didn't use my face and de-age it. They recreated it from nothing. There have been uses in the past where you take an actor and make him look a little younger. That is not what this is.

" This is in the same way that Gollum (from The Lord Of The Rings) is created from scratch. This is the first 100 per cent digital human."

Weta Digital, director Peter Jackson's visual effects company that created the Gollum character, used old photos and movie performances of Smith's from the 1990s for reference to create Junior.

Then, using motion capture technology, with digital dots on his face and close-up high-res cameras on his helmet, Smith's facial expressions were recorded in a database.

Using a model of his body, they then reverse-engineered him into Junior.

Some scenes in Gemini Man featuring both characters had to be shot separately - Smith as Brogan on the actual set (with a body double as Junior in the action scenes), and Smith as Junior in the mo-cap stage.

Seeing his younger self in this way raised philosophical questions in Smith's mind.

"Off-camera, it opens up all of the ideas of your older self versus your younger self and decisions you made in the past and how they are affecting your life now. I was so oblivious to the rules, but it was a big part of why I was able to create a lot of the things because there is a power in naivete, there is a power in not knowing. I would love to recapture some of that recklessness. I've been seeking that a little bit in the last couple years of my life," he said.

So what advice would he give his younger self?

He said: "I am coming into that place now, recognising that just because you want something, doesn't mean you are supposed to have it.

"I am learning how to just enjoy the beauty of a flower without needing to pick it and take it home. And that is just everything in the material world across the board."

WEAKNESS FOR DESSERTS

When talking about how he keeps in shape at his age, Smith confessed to a massive sweet tooth.

"I am definitely finding the energy waning just slightly. I love sweets so that is the thing I can't get around. I can literally eat cupcakes for breakfast. I can have a pie for lunch and then a little bit of cake and ice cream for dinner. If I am not paying attention, I would eat like that all the time.

"So I am realising now at 51, it has to become a lifestyle. I used to be able to do it for just two or three months. I would train really hard and then do whatever I wanted for the rest of the year. If it is not a lifestyle, I can't hold it."

Asked how he always keeps his good humour over the years, Smith - who is married to US actress Jada Pinkett Smith and has three children aged 27, 21 and 19 - shared how he overcame a couple of "critical times" in his life where he "lost the joy".

"There were a couple of traumatic events in my childhood where I learnt how to escape into my imagination. I could make a beautiful place that really blocked out whatever was happening.

"On top of that, I can always see what's funny, right? For whatever reason, at the worst of the worst moments, I can see the thing that is funny and it takes over me.

"I can be at a funeral and it is sad, and then I'll just notice the shoes that they put on the person in the casket, they don't fit. So I would say that comedy has been first and foremost in helping me move through the difficult times in my life."

The writer is the chair of the board of directors of the Hollywood Foreign Press Association, a non-profit organisation of entertainment journalists that also organises the annual Golden Globe Awards