Viggo is Good ;for You ;)

One of the things that has always fascinated me about Viggo Mortensen is the way he does ambiguity. The way he can look cruel and gentle at the same time. The way he can embrace extremes of danger and empathy.

In Good his ambiguity excels itself. He's a Nazi you can't hate because you understand him. You warm to him, even. He's vulnerable, he's vain. He has been gradually seduced into the Nazi movement. He couldn't help himself.

Before we meet, in London, I see him in the street, outside the Charlotte Street Hotel. He's crouched over his phone. He's wearing the navy and red football shirt of his team, San Lorenzo, from Argentina. He grew up there. "So these are my heroes. The one group of people or thing I support unconditionally. They can do no wrong," he says with a half-smile and sits down in the cosy-chaired library. His hair is long. His eyes are piercing, kind. Full of fun, full of melancholy.

"I don't like people who get into fights about football - or anything else. But I share the passion of the fans for this team, that's for sure."

You notice straightaway that he embraces passion and distance at the same time. Emotions that would normally contradict each other sit happily within him.

He's sucking on a straw that sits in a pot of greenish herbs. He tells me it's maté, a South American tea. He grew up in Venezuela and Argentina, where his father, also Viggo, ran chicken farms. He speaks fluent Spanish (and Danish). His parents divorced when he was 11. He moved back to New York City, where he was born, with his mother, Grace, and two younger brothers. Later on he travelled to Copenhagen, needing to unravel his Danish roots.

He worked in flower markets in Copenhagen and bars in New York before deciding on a career in acting. His first job was in Woody Allen's The Purple Rose of Cairo, and it ended up on the cutting-room floor. He was first seen in Peter Weir's Witness and then as a brutal naval officer in GI Jane. He was first really noticed as Gwyneth Paltrow's lover in A Perfect Murder and became properly famous for Aragorn in The Lord of the Rings.

His peripatetic early existence has influenced him hugely. He likes to be everywhere, even though it can get a little exhausting. Hence the stimulant tea.

I study him. His cheekbones are high, jaw chiselled, eyes sparkling. Some lines, but more from expression than age. He doesn't look 50. He lives in America's northwest, near the Canadian border, in a forest. Does he really feel he belongs anywhere or everywhere?

"Yes, that is a consequence of travelling. A positive consequence. And it helps me as an actor, because at the heart of my job is to look at the world from points of view sometimes quite different from my own. That make-believe world comes naturally to children - 'I am Wolverine, I am Batman'. But as adults we have to research it."

And research it he does. When he played a mute in Darkly Moon, he didn't speak for weeks. He would call up his son and just breathe down the phone. When he was in A Perfect Murder, opposite Gwyneth Paltrow, where he played a conman artist, he painted all the pictures in the artist's studio himself. He studied the origin of each of the 43 Russian gang tattoos that were put on to his body for Eastern Promises. His body told his story.

He can be impassioned about acting, or writing, or painting, or his music. Or equally distanced from all of his artistic and creative outlets.

He is equally at home in the edgy world of Cronenberg's A History of Violence and Eastern Promises, for which he was Oscar nominated, and blockbusters like The Lord of the Rings.

In Good, an adaptation of CP Taylor's play, he plays a German literature professor in the 1930s under personal stress. He's written a novel advocating compassionate euthanasia and has an extremely sick elderly mother. "Imagine being a German. This is a job description. Most of the books you see in my library on the movie were ones I found. They were either in German or they are early editions of Proust. It's a good library. We went to a lot of book stores. I listened to a lot of music that they would have listened to. A lot of Mahler. I spent a lot of time in Germany just looking at people."

His character in Good first of all wants nothing to do with the party. Then they flatter him because the Führer himself has read the book. "He's maddening at times. He goes from being very passive and stumbling, and thinking it doesn't seem a big deal, until finally he's got the uniform on and denial kicks in. It's an accumulation of all of these compromises. He can't run away from it any more and then he crumbles. And at the root of it he has been seduced by flattery."

There is an eyebrow-raising moment where he is in a full Gestapo uniform; his girlfriend is so turned on that she instantly performs oral sex.

"Because she is seduced by power and its trappings. That's her aphrodisiac," he says.

Have you ever been seduced by power or flattery? "I think in a fairly harmless way. Perhaps where a director might have helped me realise I could do something and I needed encouragement. But certainly as well I might have strayed away from a path without realising it and my friends might have said: 'Hey, wake up, look what you're doing.' This character was easy to relate to. It's very intimate. It's about an ordinary person."

I tell him I was frustrated by the inconclusive ending of Good, and he's pleased about that. He tells me it's not your normal Nazi story. It's not The Reader. "You know, real life doesn't just suddenly resolve itself. You have to keep working at it. Democracy, marriage, friendship. You can't just say she's my best friend. That's not a given, it's a process."

Are you good at working at things like that? Do you work on relationships? "I don't always. When there is conflict it's good to step away, even for five minutes, because you could say terrible things that you can't take back, so it's best to walk away," he says, only half-convincingly. If I am sucked in and don't walk away I become very destructive, I tell him. "Me too," he says. "I say things that are personal, that I don't really mean, because if somebody hurts you, you want to hurt them instinctively, go for something you know is going to really upset them."

The eyes flash anger, empathy, hurt. He sucks on his little straw. He tells me that it has the same effect as coffee, but without the comedown, and offers to let me try it. It tastes bitter but comes with a warm rush. He doesn't mind that I've left a lipstick mark.

Do you have to have the last word in an argument? "Only if I get really incensed. It usually has to do with fairness, or if I feel I've been cornered or misrepresented, then I will lash out. It's good to have the presence of mind to say: 'Can I call you back? Let me take a break and go for a walk.' Always better."

Do you have a girlfriend at the moment? "Well, even if I did I wouldn't talk about it," he says, but half-heartedly. No, he doesn't want to talk about anything that will get him into trouble, but at the same time he has a need to explain himself. "It doesn't really have anything to do with the job I am doing." No, but it has to do with what we have just been talking about. "Yes, of course that's true. But if you want to take care of another person, then you don't go round blabbing about them. I like the fact that the character in Good mostly tries to do his best. And generally that's what I do. I try to avoid conflict. I don't want people to be unhappy. That's why Halder, the character, is ripe for seduction. He's good at giving out all this energy of trying to keep everybody happy, and he's not getting anything in return."

Is that how you feel? "Yes, I try to keep too many plates spinning to satisfy everyone's needs, and if you are not careful you get burnt out and really stressed. You end up saying and doing things that you later regret."

Mortensen is a person who always wants to do everything and please everybody. "When I was in New Zealand working on The Lord of the Rings, there was a saying: 'One job at a time and each job a success.' I have tried actively to reduce my tendency to do everything. I cannot be so stretched."

It's a hard habit to break. He tells me he's always reading five books at a time, and part of his way of getting into the character of John Halder was to play a lot of music. He found an old Japanese piano where they were filming. So they would finish a day's shooting and instead of looking at the script for the next day, "I would just go and play and think about what we had done, where we were going. The music became as important as everything else. It was fluid and focused, with this dark undercurrent. We ended up recording it."

He will release his music as a CD. And he admits: "I did take some pictures and write a bit as well." I tell him that I've enjoyed his poems. They are wincingly emotional and embrace the minutiae of relationships, cruelty and longing. He's not particularly good at taking the compliment, and he changes the subject. He says: "I like where I live because it's in the forest, away from everything."

I read a story that when he was a child he went to hide in the forest and fell asleep under a tree and a dog came and found him. His mother retold the story that he was not asleep but he was screaming. "Yes, I was crying." It was interesting that he got contentment and abandonment confused. He smiles. "Well, I don't really know which it was, but I was always running away. I did that a lot. Another time when I was a child, about two-and-a-half, I crawled out of bed and across the road and crawled into someone's house on a Sunday morning. I was in the kitchen playing with all the pots and pans, and they called my parents, who had been calling the police. I think they said: 'You are missing someone, and he is here playing with our kitchen knives.'"

Viggo was a strange child. "As long as I can remember, when I was a little kid I have always been conscious that we are here for a limited period. Not really fearing death at all, but as a little boy I did resent it. I thought it was unfair because there are so many things to do and adventures to have. And as an adult you realise you can never read all the good books. You can't even see all the good plays or movies or travel to all the places you want to see. It's impossible. I don't resent my mortality any more; I'm just conscious of it. Life is short and there's a fine line, you know. You can be too frantic and desperate, but you can also be too lazy."

Or maybe just too tired. "Yes. It's nice to say: 'I'm going to cancel that appointment because I'm in the middle of a good book,' or 'I'm with a friend and they need to talk, so I'm not going to run off.' There are times when I've taken on too much, and you can only do one thing well."

You wonder where it comes from, this desire to please everybody, do everything, see everything, feel everything. It's strange that as a child he felt so conscious of mortality. "I don't know why I felt that but I felt that strongly, to the point of asking out loud when I was little: 'Whose idea was that? Why can't I make up the rules about how long I want to be around?' But you know, it doesn't work out that way, and that's what makes life special. Moments you have with a person you get along with really well. Things you see that are of great beauty. A change of light, a sunset, a sunrise. Things you may never see again. You grasp those moments. You don't see a bear in the wild and walk on, thinking: Oh, I'll see another bear. You just wait and watch."

Do you have animals where you live? "I have a horse [from the equine movie Hidalgo]. I met him and we got along well and I wanted to keep seeing that horse, so I bought him. He's fat and happy and lazy. And I used to have a dog, but she passed away. She was a very good friend and an interesting being. There's a book where I have a story about her demise, which is sad but funny."

Typical of Mortensen: he sees death as sad and funny. "I like cats, too. Some people who like dogs don't like cats, but I'm not like that."

What else makes him happy? "Any time I'm outdoors, whether it's in a desert or a sea or the forest. I like the elements - whatever the weather is, I don't feel that any moment is wasted at all. Even if I'm doing nothing. Especially if I'm doing nothing. When I'm out in nature it can be an inspiration. If I am going through a rough period, if I just go out for a walk, on some level everything is all right because I'm here, do you know what I mean?"

He pauses as if he really wants to know the answer. "Too much thinking, too much distraction. Responsibility. Things that are not to do with being in the moment."

Connection is important to him. Growing up, he didn't have friends - perhaps because they moved around such a lot. But it was as if he relied too early and too long on his imagination. He needs constant grounding.

He has a son, Henry, now 18, with whom he is very close. "We've never had any terrible conflicts. We've been friends for a long time and still are." He says he is also friends with his ex-wife and mother of his child, the punk singer Exene Cervenka from the group X.

"It worked out well. He always knew, no matter what, that we both loved him and cared for him, and that all we were interested in was that he should be happy and what he had to say was important to us. Neither of us tried to impose on him by saying: 'You need to do this or be that way.' We tried to set good examples, but he's definitely his own person, very strong in a lot of ways; a very good writer and musician, but also clever about maths and science."

You can tell by his poetry that Viggo is no stranger to the complicated relationship, although he's usually cagey about the specifics. He is said to have gone out with artist Lola Schnabel, Julian Schnabel's daughter, and Spanish singer Christina Rosenvinge.

"I like love to be felt equally - it rarely is, though. There are moments. When it happens it's incredible. It's like the sun breaking through the clouds, but it's a process. As soon as it's going well you think: 'We've cracked it.' It's not going to stay that way. That person that you love so much and understands you so well, suddenly the next day they say something and you think: 'They don't really know me well at all.'"

And is that most important to you - to be known by somebody? That somebody really gets you? "I am cautious about it, but when I connect strongly I want to be honest with that person, risky as it is, and I want them to be honest with me..."

Do you prefer to be the person who takes that risk? "Yes, many times. But I am happy, and it is rare that if I feel that way about them they show that they really do also. That is wonderful. That makes everything in life better. Everybody in life needs encouragement."

He's smiling now and takes more tea. "It's very good for digestion. I also like chocolate. I eat a lot of chocolate. I like them really dark, really tasty."

I tell him that I would be very happy to sit there all day, drink tea and eat chocolate with him, but I have a plane to catch. He's suddenly concerned that I don't have reading material, so he dashes up to his hotel room to get me a book of poems, El Dorado, by Dorothy Porter. "I think you will like this. She's a woman poet from Australia." He also presents me with two large chocolate squares, one wrapped in pink paper that has a handwritten "Venezuela" on it, and another in orange paper that has a handwritten "Indonesia".

I am not sure whether he handwrapped them himself or whether they came from a hand-wrapped chocolate shop. I imagine him travelling the world with a suitcase of wrapped chocolates.

I wonder if Eastern Promises changed anything for him. He got an Oscar nomination for playing Nikolai, a Russian gangster, and is remembered for being naked in a sauna. It won him a whole new league of female fans. "I think Cronenberg should have been nominated for awards for both A History of Violence and Eastern Promises," he says, dismissing the praise for himself. "My only disappointment was that he didn't get more attention."

He wonders if Cronenberg will win Oscars for something else, not necessarily as great as his previous work, but because it's his moment - "like Scorsese did, and like John Wayne did for True Grit, which I hear they're remaking". Do you want to be in it? "Ooh, I'm not sure. I don't remember all the characters. But Tommy Lee Jones could be in it - he's a good horseman."

What's coming up next for him? "Cormac McCarthy's The Road is coming out later this year. It's about a man and his son. They don't always get along, but there's unconditional love there. And I've got a book that I'm putting out, and I'm going to do a play in Madrid called Purgatorio, or Purgatory. It's about the eternal struggle of relationships, how to forgive people for the horrible things they have done. It's in Spanish, so that will be fun. I'm terrified, but that's probably a good thing."

Can he forgive people? "There are certain things that are said and done and I can forgive, but for my own good I can't associate with that person any more. 'I don't trust you, but

I can forgive you.' I can do that. Because some things you can't take back. Some things that have been said, they hurt, they linger. That's in everybody's life."

He looks at me momentarily. The hurt. The joy. And the fun. All at once in his eyes. As he turns away I see that his football shirt has been signed by a player called The Frog, who wrote: "Thank you for being simple," which I ask him to explain. Is he thanking you for being a half-wit? He laughs. "I think he means thank you for being real. He was a childhood hero of mine. A great player. Kept it simple." Simple is the last thing you would ever think of Mortensen. He's very complicated, but also very real.

Guardian