Promising Young Woman: Yes, 30-Year-Old Cassie Dresses Like an Urban Outfitters Kid — Here's Why

Carey Mulligan plays Cassandra in comedy-thriller Promising Young Woman, which is about a 30-year-old woman who has been deeply affected and broken by her past. The film, which is already garnering Oscars buzz, was written and directed by Emerald Fennell and styled by costume designer Nancy Steiner, who understood immediately how Cassie's devastating time in medical school has affected the rest of her life and, therefore, what she wears.

"[Cassie's] clothing that she wears during the daytime is a disguise and a costume . . . because she's trying to come off as this sweet, girlie, feminine, candy-colored lady, in a way to avoid confrontation."

"I think the job of a costume designer involves a lot of psychology. With any character that you're dressing, you want to think about where they get their clothes, how they get their clothes, and how they treat their clothes. Does this person throw their clothes on the floor when they get home, or do they put them in the hamper? Do they hang them up? The thing is, [Cassie's] clothing that she wears during the daytime is a disguise and a costume, the same as the things in the evening, because she's trying to come off as this sweet, girlie, feminine, candy-colored lady, in a way to avoid confrontation or anybody asking, 'What's wrong?' Because really, inside, she's a broken woman. It's a facade. [Her clothes are] something that she uses to keep the happy look outside," Steiner told POPSUGAR.

As the film progresses, it becomes clear that Cassie is angry with men for the unforgivable and illegal act her best friend Nina experienced before they both dropped out of school to suffer through the aftermath. In order to paint the picture of someone who is unable to move on from a certain time in her life, Steiner tapped Urban Outfitters and plenty of vintage costume houses for Cassie's fuzzy sweaters, kitschy romantic dresses, and even club wear — all of which you might find in any 20-something's closet.

Ahead, get the full breakdown of what Cassie wears and why her outfits carry so much weight in this film.

Cassie's Sweaters
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Cassie's Sweaters

"I started at costume houses for her, trying to find unique, interesting sweaters and clothes. I always like to include some vintage in my contemporary clothing because I think it makes it more interesting. So some of the sweaters are vintage, but there's a sweater in there from Urban Outfitters with daisies on it. For vintage, I rented from costume houses such as Warner Brothers, Universal costumes, and Palace Costume, then just filled in the rest with online shopping," Steiner said.

Cassie's Business Clothes
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Cassie's Business Clothes

"[Cassie's business] outfits were meant to basically blend in with the environments that she was in. Most of these pieces were rented, and we'd reuse the jacket and pair it with a different blouse. It was all very simple business wear — like at the bar in the beginning of the film or when she went to see the dean," Steiner said.

Cassie's "Going Out" Look
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Cassie's "Going Out" Look

Steiner confirmed the sequined tube dress Cassie wears for a night out was rented from a costume house. It was looks like these she'd style to put on a front and appear overly girlie or glamorous.

Cassie's Best-Friend Heart Necklace
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Cassie's Best-Friend Heart Necklace

Cassie wears a gold broken-heart necklace in every scene (the other half was owned by her best friend, Nina), and Steiner confirmed that the wardrobe team made the jewelry, etching "Cassie" and "Nina" on each pendant.

Designers Cassie Wears
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Designers Cassie Wears

"I didn't contact designers for this film. It's not the kind of thing you really need that high-end stuff for. The only designer that I contacted was Coco Fennell, who has a clothing line in Britain. We used a dress of hers for the date scene, which was a cream dress with big red roses, and this baseball T-shirt that she wore in the cafe with a deer and a rainbow [above]," Steiner said.

Gail's Style
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Gail's Style

"It was so funny because when I fit Laverne [Cox, who plays Gail, Cassie's boss and only friend], she was like, 'I have never worn anything like this in my whole life, but OK honey, you know what you're doing.' I love Laverne. I wanted her to feel like that comfortable mom . . . not mom-like, but like there's nothing threatening about her in those floral peasant blouses. She's just there as support for Cassie. She always looks comfortable, natural, and easygoing, and she's not hiding anything," Steiner said.