David Thewlis: ‘I was so in character, there was only one per cent of David still there. That got scary’

David Thewlis is perhaps best known these days for his role in the Harry Potter films as the lycanthropic Remus Lupin, who teaches Harry how to defend himself against the dark arts by summoning a spirit guardian with a Patronus charm.

But in his breakthrough role, Thewlis blazed a dark, fiery trail himself as Johnny, a highly opinionated street prophet-cum-conspiracy theorist, in Mike Leigh‘s landmark 1993 film, Naked. Thewlis’s searing performance won him the best actor award at the Cannes Film Festival.

Some of the visceral power of that role stemmed from the fact that, as Thewlis recalls, during the making of that film, “I had a panic attack, but that’s not a bad thing! It was in character, and it was very useful.”

The 57-year-old actor, who is relaxed and friendly when we meet on Zoom, goes on to explain that “some extraordinary things happened on that film. Any actor who has worked with Mike would report some quite strange psychological phenomena. The process was so involving. You could spend more hours a day as your character than as yourself.”

Thewlis recollects his panic-attack moment. “I was improvising with Mike and investigating Johnny talking to himself. I went into a strange place. Suddenly I got stuck with my eyes closed and couldn’t open them. I was so much in character, there was only one per cent of David still there. I wasn’t in control of my body any more. That got scary.”

So how did he get out of it? “I thought that as long as I could light a cigarette, that would do the trick. But as I had my eyes closed, I couldn’t find my cigarettes. So I was scrabbling all over the floor looking for them. Eventually I found them.

“I went to take a cigarette out, and my hand threw the pack away. That pissed me off! I thought, ‘Why the hell did you do that?’ That went on for a long time.”

When did it stop? “My eyes are open now, so it must have ended eventually. The experience was very odd, but it informed the scene at the end of the film where Johnny is having a breakdown and is no longer in control. That’s why it was so useful to have a panic attack.”

Thewlis also shone, of course, as the arty videographer Knox Harrington in The Big Lebowski, and the slippery, paranoid crime boss VM Varga in the third series of Fargo, as well as playing Lupin in four Harry Potter movies. Those films remain immensely popular, but the actor emphasises that his life has not been warped by the massive fame the franchise brings with it.

He says that he has not followed the controversy surrounding JK Rowling’s remarks about transgender people – “so I wouldn’t like to comment” – but reflects that, “I expect the Harry Potter connection to be in my life forever. It’s the nature of it.

“But I’ve been very lucky. I get recognised, but I’ve not suffered too much. It’s not a hassle in my life. I’ve never been tabloid famous. Sometimes I walk round London for a week and no one bats an eyelid.”

However, Thewlis adds, whenever fans do stop him, “It’s lovely. It’s a really nice way to make children happy. Then you realise how much those films mean to people. As time goes on, it’s something I’m incredibly proud to have been part of. It was life-changing for a lot of people.”

Born David Wheeler in Blackpool to parents who ran a wallpaper and toy shop, Thewlis started out wanting to be a rock star. He originally came down to London from Lancashire with the aim of making it with his punk band, Door 66. But he changed tack and instead decided to focus on acting, attending the Guildhall School of Drama in London.

Ever since Naked, he has taken on a tremendous range of roles, including parts in Hollywood mega-movies such as Justice League, Wonder Woman, War Horse and Kingdom of Heaven.

Now Thewlis is starring in Barkskins, a new historical drama that starts on National Geographic on Tuesday. Based on the bestselling novel by Pulitzer Prize winner Annie Proulx, this eight-part series tracks a ragtag group of misfits, schemers and dreamers in New France – the large part of North America that was colonised by the French – during the late 1660s.

The hard-pressed inhabitants of Wobik, a small settlement in what is now the Canadian province of Quebec, are living hand to mouth, struggling to found a New World in the vast, unforgiving wilderness. Many have fled a troubled past, and now they are confronting something even more challenging: the brutality of this violent, hardscrabble new existence.

Shining a light on a neglected part of European and American history, Barkskins is an unusual, gritty and compelling series. Combining elements of Deadwood, Fitzcarraldo, Apocalypto and The Revenant, it is light years away from the cosy “chocolate box” traditions of more conventional period drama.

Thewlis has great fun as Monsieur Claude Trepagny, a wild, seen-better-days dandy with flouncy hair, a jaunty maroon hat and a cane with a silver sheep-skull handle. Using indentured labourers – enslaved people who could “win” their freedom after five or 10 years’ work – Trepagny is attempting to carve out a new life by taming the endless forest that coats the landscape.

The actor says he was drawn to the character of Trepagny when “the producers referenced the fact that he has a Nick Cave, Jimi Hendrix, David Bowie atmosphere around him. He is so much larger than life. He was beautifully enjoyable to play.”

Homing in on the subject of colonialism, Barkskins could scarcely be more topical. “It’s so prescient,” says Thewlis. “It taps into the current discussion about slavery. I’d very much appreciate it if that were a talking point.”

Barkskins certainly chimes with the debate now swirling around the issue of taking down the statues of slave owners. Citing the most high-profile example in this country, the toppling in June of the Edward Colston statue in Bristol, Thewlis observes that, “I guess in the end people’s patience ran out. I like Banksy’s idea. To keep everybody happy, he suggested putting the statue back. Then below it on the plinth, you would put ropes around the statue and build four life-size bronze statues of the protesters pulling it down. In that way, a historic day would be commemorated.”

Barkskins also has a lot of very timely things to say about the destruction of the environment. According to Thewlis, “the drama takes on board the exploitation and deforestation of the world. There are little prophetic hints throughout. At one point, Trepagny says, ‘God in the whirlwind can hear us trampling his kingdom.’”

Thewlis goes on to reveal that one of his fellow cast members lived out the environmental message of Barkskins. “To get to Canada, James Bloor [the British actor who plays Charles Duquet, one of Trepagny’s indentured labourers] did a Greta Thunberg and got a boat across the Atlantic.

“There was no glamour to it at all. It was a cargo vessel, and it looked pretty bleak. He was not sunbathing on the deck! But it was fantastic that he did that very uncomfortable trip to understand what that journey would have been like for his character.

In the 17th century, the voyage from France to North America took three months. “Which is how long we have all just been in lockdown,” notes Thewlis. “Imagine being on one of those ships for that long, not knowing whether you will live or die. The mortality rate was extraordinary.”

Next up, Thewlis is due to take a leading role in Avatar 3, 4 and 5, three of the four hugely anticipated sequels to James Cameron‘s 2009 blockbuster original. The plot is a secret more closely guarded than the US nuclear codes. “I don’t know the story because you’re not allowed to read the whole script,” admits Thewlis. “This project doesn’t work like anything I’ve ever done before.”

Addressing the time that it has taken to make the eagerly awaited second and third films in the franchise, he says, “The postproduction is very long because they’re making two films at once. Sometimes they are shooting sequences from both movies on the same day in different parts of the studio.”

But they will have to get a move on. Thewlis says that “if the films are delayed any longer, some of the principal cast won’t be able to finish them as they are already committed to other projects.”

Before we log off, I suggest that Trepagny, Thewlis’s character in Barkskins, is so magnetic that he might merit a spin-off series,a la Frasier or Joey.

“That would be great!” he exclaims, bringing up the original references he was given for the character. “I play electric guitar, and during filming I would sit on my trailer steps strumming it. So a new series could feature the dream band of Trepagny, Jimi Hendrix, David Bowie and Nick Cave.

“I’m sure these days they would have the technology to achieve that!”

Barkskins begins on National Geographic at 9pm on Tuesday 4 August