David Thewlis: the secret surrealist

^'You don't often get scripts like this landing on the doorstep," David Thewlis remarks, fingernails idly digging at the skin of a satsuma. "It came along in a very unusual fashion: Luc Besson called me out of the blue one night when I was at home, painting. I didn't even know he had my number. So I was surprised, and even more surprised to be given an offer – I want you to play a lead in my new film."

The film was The Lady, a powerful account of the personal and political struggles of the Burmese democracy campaigner Aung San Suu Kyi. At the film's heart lies the relationship between Suu Kyi (Michelle Yeoh) and her husband Dr Michael Aris (Thewlis), a marriage that must somehow span the years of enforced separation while Suu Kyi was under house arrest, and the cancer that caused Aris's death in 1999.

When Besson called, Thewlis was committed to another project, with a schedule that would prevent his involvement. But the director persisted, and Thewlis relented just enough to read the script. "He emailed it to me and, by the end of the night, I'd said yes. I was very moved. I knew about Aung San Suu Kyi, the Nobel peace prize, the '88 uprisings. But I didn't know anything about Michael – that she was married to a British man with British children."

Thewlis, now aged 48, started by reading up on Suu Kyi, then truffling out information about Aris, an expert on Bhutanese, Tibetan and Himalayan culture based at Oxford university. There wasn't much to go on for Aris: an interview with Channel 4 news, another with the BBC, footage of him as their sons accepted Suu Kyi's Nobel prize – very little to build up a rounded portrait. "I was a little concerned," Thewlis admits, "because in these TV appearances he was a very solemn, sombre man – understandably, because each time they were recorded he'd just been refused a visa, or he'd not heard from her for two years and had no idea what condition she was in or where she was. He looked very uncomfortable."

He was also daunted by the process of becoming Aris – complete with fake eyebrows, prosthetics and fake mole, not to mention the task of replicating Aris's distinctive voice. "Even though this was in the late 90s, the footage looked as if it was from the late 50s. Michael was an academic, and his voice seemed from another age. So I was a little alarmed. I thought, 'I don't know how I'm going to get this voice and make him a plausible character.'"

His breakthrough came in meeting Aris's identical twin, Anthony, also an academic. "He was a guide for how Michael might have been in more uplifting moments, with more joie de vivre, more sociable elements. The Anthony I met was a very lovable, quite eccentric, very funny gentleman – though his wife was careful to tell me that Anthony wasn't Michael." There were also photographs, letters, personal recollections, and all the grief of a bereaved twin. The script that had at first felt "like fiction or history" now came alive. "The grief is very present for Anthony," says Thewlis. "He was very close to Michael and enormously close to Suu. It's something that happened to the whole family."

'My head felt absolutely on fire'

Since completing The Lady, Thewlis has done little. There has been some travelling around Europe – a reaction, he suggests, to spending two and a half years living in Los Angeles with his former partner, the actor Anna Friel, and their young daughter. There has been some painting, too, and a little writing. "I had a good year last year: I did four big films and I didn't feel like doing anything for a while. I just kept turning things down. I should probably think of doing something again now, but after Harry Potter, Anonymous, War Horse and The Lady – four really good films with four major directors – nothing has really tickled my fancy." He sets the half-eaten satsuma to one side. "But I'm not in a rush," he says. "I'm quite lazy."

Even a cursory glance at Thewlis's CV would give the lie to such a claim. Since leaving drama school in the mid-1980s, he has worked consistently in both film and television, earning a reputation as one of our finest actors. There have been appearances in Seven Years in Tibet and The Big Lebowski, Ridley Scott's Kingdom of Heaven and Terrence Malick's The New World, as well as notable turns as an SS commandant of a concentration camp in The Boy in the Striped Pyjamas, and as Professor Remus Lupin in four Harry Potter films. He has also managed to notch up a best short film Bafta for his directorial debut, 1995's Hello, Hello, Hello; written and directed a full-length feature, 2003's Cheeky; and in 2007 he published a novel, The Late Hector Kipling, about the dark side of friendships.

His first major role came in Naked, Mike Leigh's disturbing 1993 film, in which he plays the misanthropic, troubled, yet relentlessly eloquent Mancunian Johnny – a role that led to numerous awards. Will he work with Leigh again? He grows coy. "Well," he says, leaving a long pause, "it's possible. I saw him the other day. I was at a birthday party, and he was there, the little bugger, and we chatted. That's all I can say." He laughs wheezily then throws a few more crumbs: "We come across one another at social occasions and always have a little chat, 'What about … What if … Maybe …'" He smiles knowingly. "We talk around it. We're not against it."

Working with other directors came as a shock after Naked. "When I started doing the big Hollywood stuff and I realised, oh, there's no rehearsal at all, you just turn up on the set, and sometimes you haven't even met the other actor, or the woman who's playing your wife, and you're suddenly in bed with them." He looks faintly amused. "With Mike, it's not even rehearsal; it's building everything from scratch. I found it enormously creative and collaborative and fun. I felt very alive, my head felt absolutely on fire. Mike was the one who told me to write a novel. I'd made a film. Mike saw it and said, 'I don't think that's your thing. I think you should write a novel.'"

Why does he think directing wasn't his thing? Thewlis looks sheepish, glances at the half-eaten satsuma, and his accent grows more Lancastrian. "Oh," he says, "it's just too much stress. It's just awful. I'd directed a short film, and I really enjoyed it. And then I wrote Cheeky, and I was never meant to direct that. But I got persuaded to direct it, and persuaded to be in it, and that was never the plan. I didn't have a very good time and I don't like the finished product. I think it's rubbish." He shrugs his shoulders up to his ears. "Well, it's not rubbish, but it's not what it was supposed to be. It was supposed to be something much stranger. It was supposed to be very inspired by Buñuel, but you'd struggle to see that."

Giraffe: £4,000. Camel: £2,000

He has a thing for surrealism. His short film was meant to conclude with an ostrich running down the road, but upon discovering that this was how Buñuel had ended The Phantom of Liberty, he planned to use a giraffe instead. "But I couldn't afford a giraffe," he says sadly. "Four thousand pounds it was to get a giraffe. But I could get a camel for £2,000. And it was a beautiful camel. I expected a scraggy-looking thing to turn up, but on the night they said, 'The camel's here, David,' and I turned around and thought 'Ah!' because it was gorgeous."

He feels happier in the world of writing. The book he is working on now is "sort of secret, but it's another black comedy". He adds: "I'm a bit out of practice with the writing of prose, and I haven't been reading as much as I should." We discuss Julian Barnes; his struggles with 1Q84, the new Haruki Murakami; and his recent conversion to the Kindle after several eye-straining months of attempting to read entire books on his mobile phone. "I started doing it [while working] on Anonymous," he says with a laugh that is half-mocking, half-proud. "Makeup took hours and hours, and the makeup artists were German and didn't speak much English, so they would talk among themselves. And there was nothing to do for four hours. So I started reading. I must have read three-quarters of Anna Karenina on my phone. Which might be a record."

It would be remiss not to raise the subject of Thewlis's involvement with the Harry Potter series. "I kind of miss it now that it's really over," he admits. "It was mainly just a social occasion, two weeks hanging out on night shoots with Dan, Emma, Rupert and Julie Walters. It wasn't ever hard in terms of figuring out your character. It wasn't ever a struggle running around with a wand."

He gives another whiskery laugh. "But what we do is ridiculous! I think that even when what I'm doing is serious, even when I'm not turning into a werewolf." He looks up from the table, bright-eyed and a little bashful. "It's a silly thing to do, isn't it? It's what you do in the playground when you're kids – but actors just never stop doing it."