With his rangy good looks, Sam Shepard is perfect in an updated western about the exiled outlaw.

'I don’t get offered many lead roles in movies these days,” Sam Shepard says, laughing. “And if I do, they’re not very good scripts. So I haven’t been jumping on that bandwagon. But when one comes along…” He lets the thought dangle.

A couple of years ago, one did come along. “The best I’d seen in years,” says Shepard, who knows something about writing. He would play the famous outlaw Butch Cassidy, widely believed to have been killed (along with the Sundance Kid) by the Bolivian military. In this version of his life, Cassidy lived quietly for 25 more years under the name James Blackthorn in a remote Bolivian village, before yearning to return home and see his family again.

The film, Blackthorn, is a Spanish production with mostly English dialogue, written and directed by screenwriter Mateo Gil (Open Your Eyes, The Sea Inside). Much of it was shot 15,000 feet above sea level in Bolivia, which provided stunning landscapes. It was, Shepard recalls, a unique experience.

“They don’t breed many horses in Bolivia, because of the altitude. They had to import polo ponies from Argentina. I got to do most of my own riding, rather than stunt guys. I did a little singing. And I found the character intriguing. I didn’t want to do an imitation of Paul Newman (from the film Butch Cassidy and the Sundance Kid) so I did a lot of research about Cassidy.

“I thought the film might be different from other American westerns, especially as it was Spanish and shot in Bolivia. And I think it turned out that way.”

Certainly Shepard, now 68, is a plausible Cassidy; his rangy six-foot frame and weather-beaten good looks make him perfect casting for a western hero. He grew up loving horses, even working as a stable hand in his teens. “To sit on a ranch horse that’s been broken in, it’s like getting in a Porsche,” he says, beaming.

We meet in Paris. He approaches me among the crowds on Boulevard Saint-Germain, a celebrated man who has mastered the trick of going unnoticed in public. He walks alone, without a retinue. As a film actor, he excels at playing soft-spoken, self-contained men; after an hour in his company, one sees why.

He wears his fame lightly. Plays such as True West, Buried Child and Fool for Love established him as a great American playwright, a Pulitzer Prize-winner for drama. He’s a gifted actor, Oscar-nominated for playing legendary test pilot Chuck Yeager in The Right Stuff. Shepard is also a screenwriter (Paris, Texas), an accomplished musician and a film director (Far North). He has illustrious friends – Patti Smith, Bob Dylan, novelist Cormac McCarthy – who seek out his company as he seeks theirs.

He travels widely, beneath the radar, living the fulfilled life of a successful, versatile artist. He has suggested we have lunch at the famous Left Bank restaurant Cafe de Flore; even before we sit down, Shepard reminds me this was a favoured hang-out of one of his heroes, Samuel Beckett.

But why is he even in Paris? He’s also a friend of legendary theatre director Peter Brook, who lives there. Brook’s daughter Irina, who also directs, is staging a new production of Ibsen’s Peer Gynt at this year’s Salzburg Festival. “I’m helping her adapt some of the monologues, turn them into music,” Shepard says modestly.

Tomorrow he leaves for Dublin, where on Monday at the Abbey Theatre he and Patti Smith take the stage for an evening of music and readings to benefit the Abbey’s programme for new playwrights: “I’ll read from Flann O’Brien at the gig, she’ll be reading Yeats,” he says. Then it’s on to New York to discuss his new two-act play opening later this year at the Signature Theatre; he’s thinking he may call it Artless.

Perhaps it’s the rich variety of his life that allows him to treat today’s film industry with scepticism: “I don’t do much screenwriting anymore, because everyone tries to tell you what to do. On every film, there are producers all over the place, and everyone’s got to have an opinion. I think the screenplay is a beautiful form with great potential, but the environment around it is awful for a writer.

“The wonderful thing about writing for theatre is you can go anywhere you want with the language. There are no limits. With film, they frown on language – it’s always 'Too many words’.” Movies, he thinks, have suffered because of this tendency: “I recently did a film called Safe House [starring Denzel Washington] and I counted the cuts [between shots]. I don’t think there’s a shot longer than three seconds. That doesn’t give you a chance to settle into the characters, it’s unbelievable.

“But that’s the style of popular film-making today. It’s cut so hard and so fast that it takes everyone’s breath away. They can’t catch up to it. So consequently you don’t get the language, you don’t understand the movie. And in the end it really doesn’t matter what’s going on.”

In the same way, Shepard has no time for the cult of fame and celebrity. He has an agent, but never has a team of hangers-on and assistants around him.

“All that stuff just slows you down’” he says. “I think [actors] get trapped in this notion that they have to have a cushion between themselves and the world.”

Certainly he keeps the details of his life discreet. He seems to be single these days, dividing his time between New Mexico and his farm in Kentucky...

In New Mexico he lives a quiet, almost donnish life. He is affiliated to a think-tank called the Santa Fe Institute: “It’s mostly scientists, some of them very well-known, Nobel Prize-winners. There’s only a couple of writers – me and Cormac McCarthy, who introduced me there.

“We all meet up every day. It’s a way of seeing if there’s a dialogue between different [disciplines]. There’s a lot of discussion about complexity theory and neuroscience, how things control human behaviour. You run across people with different areas of expertise. It’s very cool.”

He talks about this far more enthusiastically than being in movies. “With acting you can find a way to make it interesting for yourself, if nobody else – even on big-budget films.” He sighs: “But you’re very much on your own.”