You have to remind yourself that Romain Duris is closing in on 40 and that later today, he'll return home to La Bastille to be with his actor partner, Olivia Bonhamy, and the couple's four-year-old son, Luigi.
He has dressed down, in jeans, and his artfully messy, dark hair makes one think in style section bytes such as “campus chic” and not of phrases such as “dad” or “average age of Volvo owner”.
Today, he has stopped off in one of London’s more fashionable hotels for a flying visit, but Duris’s return ticket on the Eurostar ought to, one feels, mark the first stage of a daring inter-railing adventure.
And yet, as even a cursory glance at his CV reminds us, Duris is 39 and has notched up almost two decades' worth of credits in the "biz" – stretching all the way back to Cédric Klapisch's 1994 dramedy, Le Péril Jeune .
Barring the occasional export-friendly confection – 1996's frothtastic When the Cat's Away or 2002's The Spanish Apartment spring to mind – Duris's early breakthroughs were synonymous with what, in the Anglophone world, was dubbed the New French Extremism. Not long into his eclectic career, Duris featured in Jan Kounen's seminal, ultraviolent Dobermann in 1997 and in Tony Gatlif's wilfully absurd 1999 film, Children of the Stork .
Did he feel as though he was part of a nouvelle, nouvelle vague at the time?
"Yes and no. I like to mix things up too much to say," he grins. "It is the great thing about France. The young audiences can go to a film by an author like Gaspar Noé or Ozon and, you know, that's great. We can make popular films like The Intouchables and we have some movies for export. But we still produce authors. We still produce great cinema. That's the most important thing."
Today, Duris occasionally – only very occasionally – turns to a translator for a dig-out. Mostly, he's perfectly capable of gabbling along in accented English. He speaks French only jokingly: " Moi? " he cries incredulously and more than once.
The actor had already been shortlisted twice as the Most Promising Actor by the César committee – for Gadjo dilo in 1997 and Peut-être in 1999 – when Jacques Audiard's moody 2005 drama The Beat That My Heart Skipped , catapulted Duris into the broader, international consciousness. A slanted remake of James Toback's Fingers (1978), Beat boasted a dazzling central performance from Duris and enough swagger to jolly its maker and leading man around every awards bash on the continent.
It must have changed the kind of projects and screenplays he was offered overnight, surely?
"Yes," he nods. "But this was not always a good thing: mostly what changed is that with every script the director said 'I'm going to do something like Audiard'. You read the drama and you knew the director wanted to be Jacques Audiard. And that's commendable. But nobody can be Audiard except for Audiard. It's impossible. He does things with story and character that are coherent that nobody else could make coherent."
Duris admits, nonetheless, that The Beat That My Heart Skipped impacted on his own view of himself. The "accidental actor", who was spotted by a casting director on the Metro in 1996, had, hitherto, generally considered his glittering profession as something of a joke.
“At that time, I was playing with same weapons I had again and again,” he says. “I had no method. I still don’t. I had been relying on spontaneity. Spontaneity is good but what’s great in this kind of job is that the more years you spend, the more truths and tools you have to play with. I don’t know. It’s difficult for me to speak about acting and make any sense. I have no training. It’s a mystery to me . . . ”
Born in Paris to an architect-engineer and a ballerina, Duris's training for stage and screen came through his sister Caroline, a concert pianist who taught her brother how to fake being a piano virtuoso in The Beat That My Heart Skipped . (Her playing features on the film's soundtrack.)
"She would drag me in to do little party pieces for her friends," recalls Duris. "I always loved to dance at parties. So my sister would choreograph me in little shows. I had training to be Michael Jackson. I remember that. She would gather her friends around: 'Look, my little brother: he's Michael Jackson'."
Despite this inauspicious sounding schooling, Duris has seldom been short on gravitas. To date, he's essayed the title roles in the biopics Arsène Lupin and Molière and had a crack at Leonardo da Vinci in 2007's L'Âge d'Homme . Between busy awards seasons – he has chalked up 10 major nominations to date – Romain Duris seems happy to pop up in romcoms and all kinds of confections.
Heartbreaker , his ditzy 2010 Côte-d'Azur romance, playing opposite Vanessa Paradis, remains his biggest Francophone hit.
“And it’s the film I said ‘no’ to for the longest,” he says. “I resisted. And then it turned out to be the most successful film I’ve made in terms of footfall and box office.”
He shrugs: “Maybe I’m just bad at pickling commercial successes.”
The incoming Populaire – released in Ireland next week – looks all set to bring back the Heartbreaker crowd. Pitched as a synthesis of Mad Men , Pygmalion and The Artist , the DayGlo comedy has Duris's 1950s chauvinist take on Déborah François's bumpkin as his secretary. The girl proves useless at everything, of course, but her skills as a typist are near supernatural. Her boss quickly hatches a plan to enter his charge in the National Typing Competition; he'll do the coaching, she'll get the Carpal Tunnel Syndrome.
It all goes swimmingly until she starts making puppy dog eyes at unmoveable Henry Higgins. Can she grind down his steely resolve? Will she be able to stay on task? And more importantly, will she want to?
He is, after all, kind of a jerk.
“Ha. Exactly. That was the most important thing for me,” notes Duris. “To hold back on opening his humanity, to hold back on being nicer. For most of the film he’s not open to love and emotions. But he’s typical of his time. They had no idea how to treat women.”
Populaire bears little resemblance to The Beat That My Heart Skipped . Is there anything that unifies Duris's wildly varied oeuvre ?
“I force myself not to calculate these things. It would be too depressing. I think there is a natural selection to what I do. When I read something, I’m looking for the kind of purity any reader is looking for when you read a book or a news story. I think when I want to play the guy it usually happens because it is new. But I try not to think if I have done something before or even to think if it is good or not.”
He remains an auteur theorist and turns into an all-out fanboy at the mention of Tarantino: “He is the most important representative of our art that we have for this age.”
Duris has worked repeatedly with directors such as Tony Gatlif.
“It makes the job easier,” says the actor. “I’m more attracted by directors who have their own world and who are passionate about cinema and who are trying to explain something new and different to the audience. It’s easier for me to work with and understand directors with very clear ideas.”
We do hope that thinking stood him in good stead for Michel Gondry's Mood Indigo . An adaptation of Boris Vian's surrealist classic, Froth on the Daydream , Indigo arrives here later this year, replete with an invisible car and piano cocktails. Don't ask.
"Every instruction was bizarre," laughs Duris."It was chaos. We were given new things to play with faster than we could work them out. It was chaos! Only Michel Gondry could know how to make a movie like this. No one else knows.