The filmmakers behind the latest movie in the “X-Men” franchise created the uncanny valley but with a real person.

One scene in Dark Phoenix” has a woman stepping away from her dinner party to tend to a barking dog. When she returns, she seems a bit … off. The color has drained from her face and she’s moving as if her own body is alien to her. That woman is played by Jessica Chastain, and her body has indeed been snatched by an alien named Smith, also played by Chastain.

Smith is the film’s primary villain, and a new addition to the “X-Men” movies. Her goal is to tap into, and usurp, the heightened superpowers that have turned Jean Grey (Sophie Turner) into a nearly unstoppable force. Smith is none too friendly to humanity in that pursuit.

The character has a look that is mildly off-kilter, like a trip into the uncanny valley, but using a human rather than a robot or computer-generated imagery to arrive there. The styling was minimal, but still involved a few thoughtful steps to get Chastain to this human-esque place. Below is a closer look at how.

Chastain’s light wig was inspired by some of Tilda Swinton’s screen looks.CreditDoane Gregory/Twentieth Century Fox

Chastain’s light wig was inspired by some of Tilda Swinton’s screen looks.CreditDoane Gregory/Twentieth Century Fox

The film’s writer and director, Simon Kinberg, said that Chastain wanted a look that went far in the opposite direction from her previous screen appearances. “We looked at stripping down, not just the pigment of her hair down to white, but actually stripping down almost all makeup,” he said in an interview. “She becomes this ghostly, and yet at the same time saintly looking character, depending on your perspective.”

Some of Tilda Swinton’s offbeat looks in movies were considered as inspiration. Chastain wore a light wig that helped in the transformation.

The makeup was limited to a Korean BB cream to make Chastain paler.CreditDoane Gregory/Twentieth Century Fox

The makeup was limited to a Korean BB cream to make Chastain paler.CreditDoane Gregory/Twentieth Century Fox

Chastain worked with Linda Dowds, who has done her makeup for several films, including “Molly’s Game” and “Crimson Peak.” Dowds first considered using special contacts to give Chastain’s eyes an out-there look, but decided to forgo the lenses. Instead, she kept the makeup to a minimum, using just a Korean BB cream to make her paler. “It has a tiny bit of iridescence to it,” she said in a phone interview. “It lightens up the skin to give it a little bit of a glow and create something almost ethereal, but not anything too crazy.” The idea was to give “a little clue to something otherworldly, but not completely give it away.”

A tint, not lipstick, is the only hint of color on Chastain’s face.CreditDoane Gregory/Twentieth Century Fox

A tint, not lipstick, is the only hint of color on Chastain’s face.CreditDoane Gregory/Twentieth Century Fox

For Chastain’s lips, Dowds went with a tinted treatment rather than full-on lipstick. “In these lip tints, there’s some moisture and there’s a bit of color in them but they don’t flatten out the lips,” she said. That hint of lip color was the only signifier Dowds used to suggest life in Chastain’s face. Otherwise, it is a sea of paleness, with her eyebrows nearly fading away into the light skin.The filmmakers ruled out an all-white look as too alien.CreditDoane Gregory/Twentieth Century Fox

Smith learns how to toggle between light and dark. She needs to seem as if she’s going to Jean to help save her, even when her intentions are more nefarious. That duality also speaks to the larger themes of the movie, which deal in these contrasts. To assist with this visually, the filmmakers paid special attention to Chastain’s costumes.

When Kinberg and Chastain first spoke of the look, he said, she was interested in the idea of her character being clinical, almost like a doctor. So in addition to the pale skin and white hair, she wanted to wear white. “We tested that,” Kinberg said, “and it all started to feel too clinical, too alien.”

“When we put her in black clothes,” he continued, “the juxtaposition made her feel slightly off, but not so much so that if you saw her walk into a bar you would think, well that’s an alien.”

Daniel Orlandi (“Logan”) oversaw the costuming for Chastain, who was dressed primarily in two black outfits. “The black helped make her skin almost translucent,” he said. “It created a chic look, and her silhouette became much stronger when we darkened everything.”

Orlandi decided on a long coat with a little movement. “We tried some blazers, but that just seemed kind of common,” he said. “We wanted her to not be common, but also not flamboyant.” The result is something that feels calming, while projecting a sense of menace at the same time.