How War’s Costume Designer Separated Sienna Miller From Her Character: ‘It Is a Bit Meta’

At its most basic, an actor’s job is to remove any sense of self and fully become another person. But what if that character is similar to the actor playing the role? It’s something that costume designer Matthew Price had to carefully consider for War—HBO’s new divorce drama created by Killing Eve writer George Kay—when creating the wardrobe for Sienna Miller’s character Carla Duval.

Like Miller, Duval is a British, Hollywood-famous actor who doubles as a fashion plate with an enviable wardrobe that is as good at serving up era-defining red-carpet looks as it is at sumptuous stay-at-home knits. So far, so Sienna.

“Having a character like Carla was gold dust,” Price, who immediately jumped at the chance to work on War, tells ELLE. “As she is played by an actor such as Sienna, it is a bit meta. Especially when you think about what wardrobe she must have at home.”

Price and Miller hit it off immediately, with both already on the same train of thought for how Duval—whose divorce from Dominic West’s tech boss Morgan shapes the plot—might dress. “From the first Zoom, I knew we were on the same page as we both mentioned [magazine editor] Claire Thomson-Jonville as a reference. So, you’ll see that French minimalism in what she wears, but we didn’t want to be set in stone with one silhouette.”

Although things appeared meta on the surface, Price also had the task of transforming Miller, ridding her of her extreme fame and building her into someone else extremely famous.

“It was a real balancing act,” admits Price, who at times had to avoid items from Sienna’s favorite labels. “We had a couple of things from Chloé that we tried on, and we didn’t even have to say it, but we both knew that they felt a little too Sienna. But that helped us find Carla quite quickly.”

The differentiation between the actor and her character is plainest to see in the exceptional archive pieces that Price and his team of 30 sourced for the show.

“I instantly said to Sienna, hoping that she would agree, that I’d love to use a lot of archive pieces and go right back, maybe even back to the ’80s, if it feels correct. And she was instantly on board, saying, ‘Give me some of that archive.’”

The pair called in items from the contemporary collections of designers like Fendi and Stella McCartney, but also used pieces from & Other Stories, The Frankie Shop, and Agolde to ensure the wardrobe felt modern, and not too costume-y. “We didn’t want it to feel totally unreachable,” Price says. “Sienna wasn’t precious over labels, either. If it was the correct fit, it was the correct fit. But once I got into those archives, I recognized that those were the pieces we were missing.”

The treasures he dressed Duval in really run the gamut of best-in-class designers. There are Dolce & Gabbana pinstripe suits, a Comme des Garçons gown laden with tassels, and a particularly fantastic McQueen coat from the 2000s. What’s best about these pieces is how Price has cleverly woven them into the wardrobe, to allow them to appear natural to the character’s taste and changing preferences as the series moves on. “We asked ourselves: ‘Should we make them look naturalistic, or do we want them to look showier, more peacocky?’ It was a really fun process with Sienna, I must say.”

Price found Miller was also a helpful advocate when it came to meticulously sourcing specific pieces from archives and collectors to loan or sometimes buy. “They’re real experts,” Price says of these keepers of fashion history. “And they can be impossible to get into, but I think once they knew it was for Sienna and they started seeing some pictures on the sly, they were very excited by it and opened up the doors a bit more to us.”

With the story tracing the divorce of this high-powered couple, there had to be moments where fashion was used not only as a sense of armor but also with the idea of “revenge dressing” in mind.

“For us, that comes in episode 2. It’s a paisley Chloé jacket with black leather boots. That’s the revenge outfit,” Price confirms. “We always talked about it being that.” It’s a soft-power outfit that feels less obvious than choosing a sexy figure-hugging dress or a mannish suit, and it’s in that nuance that Price helps the character feel at her most real.

“I’m really proud of how we managed to flesh out the wardrobe and make it quite chameleon-like, in a way,” Price reflects, adding that there isn’t a single piece that best defines Duval’s look. “But I personally love the fringed Comme des Garçons gown that she wears a couple of times into the court scene later on. I wasn’t sure if I’d find a moment for that. I wondered if it felt too theatrical, in a way, but we did it.”

Yet, for all the labels and archive selects, the biggest feat that Price and Miller achieved together might just be keeping her pregnancy hidden throughout. “We also had this other challenge of how we keep true to the character, but also how do we hide the fact that she is really quite heavily pregnant?” Price laughed. “But Sienna was fantastic in the fitting period, and we just always found the right thing.”