‘Game of Thrones’ star Maisie Williams’ nightmare process to lose 25 pounds for role of Catherine Dior

Maisie Williams explained how she lost 25 pounds to turn into an emaciated Catherine Dior for the French Resistance series, "A New Look."

Williams, 26, detailed the process in a new interview. The actress portrays Catherine, a heroine in the French Resistance during World War II. The show is based on the book "Miss Dior," which follows the story of Christian Dior's sister. Catherine was 26 when she was arrested and tortured for her involvement in the French Resistance.

"I was eating very little, meditating all the time, burning candles and incense in my apartment," Williams told "Miss Dior" author Justine Picardie for Harper's Bazaar UK of how she completed her transformation into Catherine Dior.

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The majority of Williams' weight loss came from sweating out fluid right before the AppleTV+ series began filming.

"I had to be up at 4 am to start sweating," she explained. "The night before, at about 7 or 8 pm I was allowed to have something salty and dehydrating – some smoked salmon and a tiny glass of wine. Then I had a boiling-hot bath with lots of salts in it."

"And I sort of levitated to bed and slept for maybe three hours, and woke up and had a handful of nuts. I wouldn’t be able to sleep through the night at this point. I kept waking up and feeling like a marble inside a bottle, rattling around..."

Williams gained fame for her role as Arya Stark in "Game of Thrones." Preparation for that role required "building different muscles." However, Williams said the role of Catherine "took over what I’m eating and how I’m moving and sleeping and thinking. . . . "

Along with her insomnia, Williams had dreams about Catherine while prepping for the grueling role.

"There was a lot of feeling restricted, almost like sleep paralysis, dreams of being trapped and attacked, and horrible visions of men in uniform," she explained to the author.

Williams chose instead to focus on the positive aspects of Catherine's story. She went on to grow roses in Provence while her brother created one of Dior's most famous scents in her honor, Miss Dior.

"Every day of filming was a reminder that we were portraying a story of the horrors that humans are capable of inflicting on one another, but also the magic and the hope and the love. . . .  Ultimately, we wanted to make a show that was uplifting."