By Daniel Okafor

Sienna Miller's soft waves in HBO's legal drama War sometimes came from sleeping in a loose plait. No curling iron required. "To achieve Carla's waves, try sleeping with a loose plait in your hair, as this way you may get away with not having to use a hot tool," hair and makeup designer Tara McDonald said. "Sienna did that from time to time!"

Miller plays Carla Duval, a movie star navigating a public divorce from tech entrepreneur Morgan Henderson (Dominic West) in the series. Carla's life unravels on screen. Her look never does.

McDonald designed the character's aesthetic around restraint. She describes it as "a kind of understated elegance that feels innate" rather than constructed. "Even in her lowest moments there is still a sense of control in how she presents herself," she said.

What does this change for viewers who want the look?

The answer is skincare-first and tool-light. McDonald's method leans on skin prep and overnight hair setting, not heavy product layers. "I focused on luminous and beautifully hydrated skin," she said of her approach. "For makeup, we settled on subtle definition around the eyes and a neutral lip that enhances rather than transforms her natural features. Nothing feels overly done, but every detail is considered."

Hair followed the same principle. "Polished but never rigid, soft natural movement and a healthy sheen," McDonald said. "It was important that she looked like someone for whom elegance is second nature, even when things are falling apart beneath the surface."

For hair health, she is blunt. "Focus on condition by having lots of treatments, and get a great colorist!" On set, McDonald used Oribe and Shu Uemura on Miller's hair.

Two faces of Carla Duval

McDonald built two distinct looks for the character: a polished court appearance and a stripped-back at-home version. "The contrast was to show the difference between the person Carla presents to the world and who she is when nobody is watching," she said.

Both started from Miller's own signature makeup. "For the court look, I elevated it, keeping the skin fresh and luminous but adding more definition around her eyes and more color on her lips and cheeks," McDonald explained. "It was important that she looked confident, composed and in control without the makeup ever feeling too done."

At home, less. "I would strip everything back. The skin feels more real, the eyes are less defined and there's a more relaxed, lived-in quality to the makeup. A bare elegance," she said. "The idea was to make subtle changes to her signature makeup that could reflect where Carla was emotionally."

The product list

On Miller, McDonald used Chantecaille, Haus Labs and MAC makeup, plus Charlotte Tilbury lip liners and lipsticks. Her picks were field-tested. "I have been working in film and television for many years now. I've developed an instinctive understanding of which products perform beautifully on camera and withstand the demands of a long filming day," she said. "For War my choices were highly considered. I wanted the makeup to feel natural, authentic and effortless — it's quiet luxury!"

McDonald's step-by-step

Her core advice: "Don't overdo it. Spend time on skin prep. Use lightweight products that allow the skin to breathe and only use foundation where required. It is not necessary to completely paint your whole face."

• Eyes: "Define the eyes using a soft pencil (my favorite is the Victoria Beckham Kajal liner) and then blend the line with a soft brush."
• Brows: "Brush your brows and fill them in, but naturally."
• Lips: "Choose a lip pencil close to your own tone and try it with a hydrating balm."
• Cheeks: "Pop a cream- or gel-based blush high up on the cheeks and across the bridge of your nose."

The men: invisible makeup at $72

For the male cast, McDonald aimed for makeup the viewer never clocks. "My approach to male grooming is to always keep the skin looking as natural and believable as possible. It should be almost invisible," she said. "I'd hate for the audience to spot makeup on the men!"

Her go-to was Chantecaille's Just Skin Tinted Moisturizer ($72). "It gives a beautiful, lightweight finish that subtly evens out the complexion without looking like foundation," she explained. "It allows the natural texture of the skin to show through, which is important when filming in high definition. I work with very sheer layers, only adding coverage where it's needed rather than covering the entire face."

For West's Morgan Henderson, she mixed shades darker than his natural tone. "I wanted him to have an effortless patrician glow," she said.

The whole philosophy compresses to one line from McDonald: "It's about looking impeccably put together, but without looking like you've tried too hard." For viewers copying the look at home, that translates to a plait at bedtime, conditioner in the shower and foundation only where needed.