Viggo Mortensen first met Lance Henriksen when he shot him dead. Mortensen, the Lord of the Rings star and three-time best actor Oscar nominee, was facing off the older actor – a veteran of more than 200 movies including Aliens and The Terminator – in the 2008 western Appaloosa. “There were so many bullets flying around; I don’t think any one person can take the credit for killing me,” smiles Henriksen, his voice sandpapery but sweet. As we wait for Mortensen to join our video call, he says he is tip-top today. “I turned 80. But I don’t feel no 80.” Then he switches the subject abruptly. “I can’t tell you how much Falling has changed my life,” he says. Falling, Mortensen’s debut as a writer-director, provides Henriksen with the meatiest role of his career. He plays Willis, an elderly farmer whose dementia does not bring out the worst in him so much as takes his lifelong rage to a new, unmanageable level. The test for Willis’s son, John (Mortensen), who has a husband and a young daughter, is how to extend compassion to a man who has rarely expressed any of his own. Henriksen’s distinctive features have haunted cinema screens for almost half a century – that drawn face, those goggle eyes in their deep-scooped sockets, the high forehead and prim lips. His first paid gig was as a prison yard extra on The American, a 1960 TV special with Lee Marvin. “I was in jail myself at the time for vagrancy. They paid me $5 and I told the guard: ‘I’m not a vagrant any more!’” He even asked Marvin to spring him from the slammer. “He looked at me, like: ‘Hold that thought,’ and walked off. Hahaha!” He has led an astonishing life. As a young waiter in an oversized tuxedo, he once served John F Kennedy; he became friends with François Truffaut when they appeared together in Close Encounters of the Third Kind; as well as Steven Spielberg, he has worked with titans such as Sidney Lumet, Kathryn Bigelow, James Cameron and John Woo. But he has never had a part like Willis. “I was wondering if I was good enough to pull this off. I didn’t wanna get caught acting.” At that moment, Mortensen pops up on screen from his home in Madrid – “Hey, there he is!” Henriksen calls out cheerily – and digs into explaining why he picked this leading man. “Lance’s presence can be quite intimidating,” says the 62-year-old in his serene, soothing tones. “If he’s not smiling, it’s like you’re looking at a wolf who might gobble you up. But he’s also really honest. It doesn’t matter if it’s one scene in some out-there genre film, he’s always believable.” Henriksen chips in: “I started out a shitty actor,” he says. I tell him that I beg to differ, brandishing as evidence my Blu-ray copy of Dog Day Afternoon, Lumet’s sweaty 1975 masterpiece about a botched bank robbery, in which he has a vital role in apprehending the hapless Sonny (Al Pacino) and Sal (John Cazale). “That was my first movie!” he says delightedly, as though greeting an old friend. Indeed. But why did he have to go and kill poor Sal? “Ah, he had it coming,” he says, laughing. He says a lot of mean things in Falling. Asked if any of it gave him pause, he admits he felt rotten tearing strips off his co-star Terry Chen, who plays his son-in-law. Mortensen also recalls him repeatedly failing to make eye contact with Laura Linney, who stars as his daughter, during a profane dialogue scene. “Remember that, Lance? You looked like an embarrassed eight-year-old. Laura told you: ‘I’m a tough broad, I can take it.’” Then there was the day that David Cronenberg – who directed Mortensen in A History of Violence, Eastern Promises and A Dangerous Method – stopped by for a cameo as Willis’s colorectal surgeon. “I didn’t realise who he was,” says Henriksen. “What did you think of him as a proctologist?” Mortensen asks. “He really liked his job,” he replies. “Too much, maybe!” Months later, the penny dropped. “I told Viggo: ‘I saw you in an interview with the proctologist!’ I wish I’d known it was Cronenberg; I could’ve brown-nosed the shit out of him.” The pair giggle happily together. Although Mortensen’s late father had dementia, the film is expressly not a portrait of him. “He was a much better communicator than Willis is and we had a better relationship. But there are enough traces of him in what Lance plays – fragments of conversations we had, some difficult moments – that it was constantly moving for me to see.” He was determined to be honest about the illness. “Movies which deal with this subject generally show someone who’s confused. My experience is that this isn’t the case – it’s the ones observing the person who get confused. Memory is subjective anyway. Why is his present any less valid than yours? If your father is saying he had breakfast with someone you know has been dead for 30 years, don’t say: ‘He died years ago,’ say: ‘What did you guys eat?’ On some ethical level, you think: ‘I’m lying, I’m bullshitting.’ But you’re giving something that makes them feel good. It’s not about you.” This reminds Henriksen of the time he worked in a retirement home, where he took it upon himself to write to residents who never got any post. “I’d put a letter in their box to cheer them up. You should’ve seen the difference! They were bopping around the lobby. It was good for an actor to do.” “It was also a generous thing to do,” Mortensen says. Henriksen mulls this over. “The greatest choices in my life were things that made other people happy,” he says. I steer him back to his earlier comment: what did he mean when he said he did not want to “get caught acting” while playing Willis? “I wanted to live it,” he says. “I knew I’d have to go back with a clear-eyed look at how my parents behaved towards me. I had a very rough childhood. I got bludgeoned a lot. Different people, relatives. I remember every single face from my childhood. My alcoholic uncles, whoever. I’m not having a pity party here; I’m not Quasimodo. That’s just how it was.” Mortensen learned about Henriksen’s childhood during the years when they were waiting for the film’s financing to come together. “We worked on the script at his house and he would tell me these stories that were like the severest parts from Dickens.” One time, Henriksen’s mother, an alcoholic shacked up with her fourth or fifth husband, had pressed his birth certificate into his hand and said: “You’ll always know who you are.” Then she shoved him out into the night; he was no older than seven at the time. “Lance, I told you it was incredible that you were so forgiving. And you said: ‘It took me a long time to get there. I’d already been through that shit once, so why would I wanna be stuck in it?’” Henriksen takes up the story. “When I was 12, I left home. I mean, really left. I quit them – I’d had enough –and I started working at becoming a man. I rode freight trains, hitchhiked; I even worked in a mine operating a drill. At 12! Nobody gave a shit. But the fire from all the isolation and neglect and hunger never really left me.” Acting provided him with a belated sense of solace and family. “I found all these people who were struggling for some form of authenticity, romance, adventure. All that good shit healed me in so many ways.” Taking on Falling meant reopening old wounds. “I wanted to do it. But I knew it would be tough sledding some days.” Mortensen has heard all this before, but he listens intently. There is no indication that the two men are close to exhausting their fascination with one another; our allotted 40 minutes has stretched to nearly twice that length and they are going to Skype together once the interview is over. (“I gotta go out first or the dog is gonna piss on the floor!” says Mortensen.) Nor has the director tired of praising his actor. “You gave so much more than I could’ve hoped, Lance.” Henriksen looks visibly moved. “We did it,” he gasps. “We won the fucking Superbowl!” Falling is released in the UK on 4 December