Stefano Pilati: Wardrobe master

Stefano Pilati of Yves Saint Laurent has just the credentials to create the costumes for a new staging of Pinter's 'Betrayal', says Susannah Frankel

The latest staging of Harold Pinter's Betrayal is nothing if not well-dressed. Directed by Ian Rickson and with Kristin Scott Thomas, Douglas Henshall and Ben Miles in the leading roles (in fact, with the exception of a solitary waiter, the only roles), the costumes come courtesy of the Yves Saint Laurent creative director, Stefano Pilati.

Pilati has been at the helm of France's most famous status label for 11 years now, in his current role for seven and, prior to that, alongside Tom Ford, his predecessor. He today has a grasp on a history that many would find – and indeed have found – overwhelming. Under Pilati's watchful eye, Yves Saint Laurent has retained its quintessentially Parisian and essentially bourgeois elegance and discreet focus on the creation of a modern wardrobe, over and above the "look at me" fashion statement, in a manner in which even the house's namesake himself might have been proud. Pilati's Saint Laurent is contemporary, and fashionable of course, but even the more directional pieces never upstage their wearer. There's a timelessness, too, to much of it that is well suited to an era where the irony of shopping till we drop is no longer deemed chic – or even strictly seemly.

"Yves Saint Laurent is more than a fashion house and a man's name," Pilati says. "It has developed into a culture, a universe of codes and ideas. Parisian chic, French elegance and a transgressive attitude has always been part of that, but what has always been important to me is to bring the story forward without losing track of the immensity of the heritage..." And part of that heritage, of course, comprises the relationship Yves Saint Laurent – both the fashion house and the man – had with the arts more broadly. "Our participation in Betrayal comes from the notion that a fashion house can be an active part of a conversation in the performing arts," Pilati says.

Collaborations such as this one are rarely pulled out of the ether, particularly if they are to be successful. Pilati has known Scott Thomas for some time and she's regularly seen in his designs. Once the powers that be at Yves Saint Laurent discovered that she was playing the lead in the play, they contacted Rickson and the producer, Sonia Friedman, and things developed from there. "I have long admired Kristin for her talent and for her elegance," Pilati says. "She has stayed true to her craft and has avoided the Hollywood spin cycle. She has been close to the house since I became creative director and I have designed looks for her in the past for various occasions. This collaboration, while new in terms of context, began naturally because of that relationship."

The fit goes deeper than that, though. "I am compelled by the celebration of individualism in Pinter's work, by his acceptance of the world as complex and ambiguous," Pilati says.

Set in the 1970s, Saint Laurent's heyday, Betrayal is based on Pinter's extramarital affair with a young Joan Bakewell. Its undercurrents of both sexual voracity and vulnerability, escapism and sadness, require just the understated but always suggestive wardrobe that his name is known for. Most famously, Yves Saint Laurent dressed Catherine Deneuve for Buñuel's 1967 cinema classic Belle de Jour. Belle, the eponymous heroine, is the archetypically polite grande bourgeoise by day and a prostitute by night. The buttoned-up, neat little day coat, pencil-skirt and blouse, all of which were Saint Laurent signatures at that time, were perfectly suited to the repressed eroticism at the heart of the character.

"Indeed, this is a subject we understand," Pilati confirms (he also worked on Isabelle Huppert's costumes for a new production of Tennessee Williams' A Streetcar Named Desire in Paris last year). "Obviously, medium, plotlines and contexts differ between the two [Betrayal and Belle de Jour], but it is true that in both cases the costumes must convey a fragility and innocence, and then a knowing shift towards a more physical sexual self."

More generally, the characters in Betrayal – Emma is a gallerist, Jerry and Robert are a literary agent and a publisher respectively – are here shown to be fashion-conscious but never at the expense of seriousness.

"These characters were not fashionable per se," Pilati argues, "but they had definite style. Their clothes were a part and reflection of their identity, so there is meaning and symbolism in them. As someone who grew up in the same era, and with visceral remembrances of the time, I had an instinctive understanding of what the costumes needed to be."

The play is not styled in an obviously nostalgic way, however. "Ian's concept was to stage a play set in the Sixties and Seventies but to not make it overly 'period'. The story is universal and when presented today should have a contemporary spirit to it. My objective was to provide costumes that would facilitate this, not stand out in an obvious or distracting way... The Seventies feeling is certainly traceable in the result, but it appears in a touch or detail."

The Pinter play runs, with the exception of two pivotal years, backwards chronologically, beginning, wearily, in 1977, and long after the affair between Emma (Scott Thomas) and Jerry (Henshall) has ended, and closing, in 1968, with their relationship in its infancy, and with all the sexual anticipation that goes with that.

Jerry is every bit the urbane professional, dressed in turtleneck sweater (Saint Laurent appropriated this look from the Beat generation in the late Sixties and caused more than a few ripples when he sent it down the catwalk), suede safari jacket (another of the house's signatures from that period), straight pants and desert boots. "We keep Jerry in the same essential look throughout the play," Pilati says. "As he is in eight of the nine scenes, he becomes some sort of holding figure, keeping our focus on the procession of memories."

Cuckold Robert is more buttoned-up and suited, "which reflects his tension, his uptight grasp of things", the designer continues. "Emma's wardrobe is more varied, she changes more often and the character is therefore visually more dynamic. With Emma, we are also playing with time and innocence and its loss. Colour comes with her movements through the narrative. Her youth is more saturated and as she ages and the affair develops the colours fade with the memories."

It almost goes without saying that such an apparently effortless, not to mention quietly meaningful, appearance is far from easy to achieve. "My Paris team worked in close collaboration with the costume designers Jeremy Herbert and Edward Gibson throughout the process," Pilati says. "In the weeks running up to the dress rehearsals they were in contact daily, conducted fittings in Paris and London. We were also in continual discussion with Ian and the actors. In the end, the vision had to be correct and true for the play to work with Ian's conception of it. My contribution was to guide that vision with my designs and sensibility."

Such a democratic mindset is not part of the process where designing a runway collection is concerned, although pieces from Pilati's current collection for Yves Saint Laurent as well as the archives since his arrival have been used alongside specially commissioned designs.

"The approach is completely different," Pilati says of the experience. "With actors there is clearly a personality and narrative to consider. The clothes are not uniquely at the service of themselves or there to communicate a fashion statement as they can be when a designer dresses models."

A suspension of ego is required here, then, that is not generally perceived as part of a fashion designer's job description. "Ego figures very slightly," Pilati says, "because this project is a true and rich collaboration. None of us wanted a fashion show or parade. My role has been to design and produce the garments, to style looks, to make proposals and to offer ideas. Then the creative force of the production team gave all that a reality onstage, in the spirit of the production."

And that, in the end, is a mutually beneficial situation.

"It brings a vitality to the house, an engagement with culture outside of fashion and an integration into society at large that extends beyond a branding exercise or simple PR. I am honoured to have had the opportunity to collaborate on the production," Pilati says.

Betrayal premieres at the Comedy Theatre in London on 16 June.