'It's about two poor boys who spend their life playing tennis...the emptiness of that success'
He found fame in Good Will Hunting, Pirates Of The Caribbean and Thor, but now Stellan Skarsgard is playing Bjorn Borg's coach in a new film about the epic tennis clash between Borg and John McEnroe.
When thinking of the great sports films - from Raging Bull to Rocky, Chariots Of Fire to Any Given Sunday - it's rare for a tennis film to cross one's mind.
Dramatising the tension of a matchpoint and the repetition of a rally is notoriously difficult to do, while it is also a major task for actors to master the footwork and technique of tennis champions convincingly enough to play one on screen.
But not one but two tennis films are now arriving in quick succession - Battle Of The Sexes, starring Emma Stone and Steve Carell as Billie Jean King and Bobby Riggs, and Borg Vs McEnroe, starring Swedish actor Sverrir Gudnason and Shia LaBeouf as cool-headed champion Bjorn Borg and the volatile and ambitious John McEnroe.
The second tells the story of the fierce rivalry between the two, building up to their 1980 clash in the men's singles final at Wimbledon, when Borg was a three-time victor and McEnroe the prodigy eager to dethrone him.
Stellan Skarsgard, star of Mamma Mia, Thor, Good Will Hunting and The Girl With The Dragon Tattoo, plays Borg's devoted coach Lennart Bergelin and says the film achieves what is so hard to master.
"It's very hard to do," he says. "I've never seen it as well done as in this film. You can always put in the balls with CGI afterwards but you cannot change the body language.
"Shia and Sverrir, the way they move, their footwork, everything, it looks so real.
"I asked Bjorn Borg himself after the premiere what he thought about it and he said 'yeah it's real' and that was a good compliment from him to those guys."
As the build-up to the match unfolds, the film slips back in time to show Borg's early start as a gifted but volatile child and McEnroe's experiences of pressure and expectation in his formative years.
"There are no bad guys and no good guys in this film", Skarsgard says, "and it's not about who is going to win really, it's about those two poor boys, their lives are f***** up already, spending their entire life playing tennis instead of reading books and having friends and sleeping with girls and stuff, important things.
"The emptiness of that success and that fame was a big ingredient in the film and it gives the film a life of its own beyond the sport.
"You don't have to be interested in tennis to see it, you don't have to know who Borg or McEnroe is to see it, it stands on its own legs."
Skarsgard does not count himself as a tennis fan but remembers that match as a national event in his native Sweden.
"I remember it because it was a drama, everyone in Sweden watched all his matches, but that one was fantastic," he says.
"It was so well-built, the perfect drama, except that the tie-break should have been in the last set and not in the second-last set.
"I remember the pain and anxiety when he lost match ball after match ball.
"Sverrir's transformation is fantastic because he was skinny and had no muscles, he was a little floppy. His diet was mainly pizza and beer, and then he had to be this athlete and he worked so hard, he got a new body.
"The most fantastic thing was the first time I saw him as Bjorn Borg on the set, he walked like Bjorn Borg and it was really weird to see Bjorn Borg come back in real life in that way."
Like the tennis players, Skarsgard (66) also became famous as a teenager, with the title role in the Swedish TV-series Bombi Bitt And I before Hollywood and English-language projects beckoned, so the spotlight that the tennis stars lived under was familiar territory for him.
"The problem with fame is if you try to live up to the expectations of society and the media and everything, then you will ruin your life.
"If you allow them to inflate you too much you will ruin your life, so throughout my career it's been very important for me to make sure that nobody thinks I'm better than I am, I sort of deflate anything that resembles any (thing like that), eventually it will kill you."
LaBeouf's own struggles under the harsh glare of flashbulbs have been well-documented, but Skarsgard is keen to come to his co-star's defence.
"This is my second film with Shia but I've never had a scene with him, but I like him as an actor very, very much and he is a very, very sweet person," he says.
"He has had some troubles here and there, alcohol-related usually, but that is such a prominent part of his image thanks to the f****** media.
"You shouldn't care about that, because he is truly lovely and truly nice.
"I didn't have scenes with him but I hung out with him a lot, and what he does to this portrayal of McEnroe is something really beautiful, because you end up loving the guy and feeling for him."
Skarsgard himself will be the subject of long-lens photographs when he reprises his role of Bill in the highly-anticipated sequel to Mamma Mia, alongside original cast members Meryl Streep, Colin Firth and Pierce Brosnan, and a bevy of newcomers who will play them in their younger years.
Photographs of Lily James, playing a young Streep, have already emerged, alongside Josh Dylan, playing a young Bill.
So how does it feel to see another, younger, actor play his part? "I think it's fine, it's lovely. He's a very nice actor, I'm really happy with the choice of me as a young man," he says.
One of his sons - he has seven including Big Little Lies and True Blood star Alexander - auditioned for the role but was unsuccessful, he says.
"Of course one of my acting sons, I have four acting sons, the youngest of them, I think he applied for the role, but he sings, if possible, even worse than I do, so he couldn't get it."
- Borg Vs McEnroe is in cinemas from today province-wide