Viggo Mortensen: Star reveals emotional journey on the road to his latest role

Everyone who has read Cormac McCarthy's 2007 Pulitzer Prize-winner The Road has a take on what it's about and whether it should ever have been made into a movie.

What makes Viggo Mortensen different is that he hadn't read the book when director John Hillcoat asked him to play the dying father who shepherds his young son across an America shattered by some mysterious, unexplained cataclysm.

"I have read all McCarthy's books, although this I read as a script first," says Mortensen, now the thinking director's actor of choice after his stupendous success as Aragorn in Lord of the Rings.

"The Road is really just about the journey. What do you learn along the way, if anything, and what do you figure out about the questions 'Why survive?' and 'How do you survive?'

"A conclusion you can come to from the book, and what I think comes through in the movie, is that when everything has gone the thing you think you're looking for – warmth, shelter, food, nice people, sunshine – it's not about that. It's about what you are taking along with you, which is each other, and whatever is good inside you. It's a choice you can make."

There are those who believe The Road was one of those famously unfilmable novels and that it should have been left alone. Mortensen, a free thinker, aesthete, poet and 21st century method actor is firmly of the opinion that Hillcoat and his cast (which includes veteran Robert Duvall and fellow Oscar winner Charlize Theron alongside Mortensen and young Kodi Smit-McPhee) have nailed it.

What's more, the famously publicity-shy author, now 76 and the father of an 11-year-old son, John Francis, to whom the book is dedicated, appears to agree.

"We were shooting the sequences by the sea, and he came with his son to watch. He said 'That's just how I imagined it'. It was great to see his dynamic with his son, too. It reminded me of the book. They're clearly very close."

Mortensen describes McCarthy's book as "strangely affecting and very grounded in reality" adding "it's clean as a story".

When asked to expand he adds: "There's no strange twist or gimmick; it's not genre, not self-conscious. It drives you on. You know where you are going but you can't stop paying attention. It's like someone has done something that really gets to you; it's very real. It can't possibly end that well! In fact, it does and it doesn't."

As the weary traveller, armed with a revolver loaded with two bullets (for protection or to finish the boy and himself in the face of certain death?), Mortensen opted for that old actor's stand-by – the emotional truth of the character.

An anonymous character (he is known only as The Man), he was brought to life by Mortensen through accent, a back story he authored and kept in his head and a vision of humanity clinging on in spite of the horrors all around.

"People have asked what happened to the world in this story," says Mortensen "but that doesn't really matter. You're just finding a situation where everything is stripped away and you can put a spotlight on people's actions, feelings and choices."

He added: "At the end, the father can't really answer one of the two questions we mentioned, 'When it comes to survival, how?' You can never really know. But you can know why you'd want to stay alive – and why you'd want the boy to stay alive – in that terrible world."

Epic made actor star

Viggo Mortensen was born in New York on October 20, 1958 to a Danish father and American mother. His father managed large farm enterprises in South America when he was young.

Mortensen's acting career began on stage and with minor roles in films, but being cast as Aragorn in The Lord of the Rings trilogy in 1999 made him a star. At first, he didn't want to do it, but was talked into it by his son.

He is also a prolific photographer, poet and musician.

In 2007 he was Oscar-nominated for the film Eastern Promises, directed by David Cronenberg, in which he played a Russian gangster.

He has a son, Henry, with his ex-wife and singer Exene Cervenka.

In his own words: "There's no excuse to be bored. Sad, yes. Angry, yes. Depressed, yes. Crazy, yes. But there's no excuse for boredom, ever."