“The way Elle transforms like that is incredible,” says The Girl From Plainville costume designer Mirren Gordon-Crozier. Just two weeks after wrapping season two of the historical comedy The Great, Fanning pivoted from 18th century Imperial Russian regalia, by Sharon Long, into the oversized T-shirts and printed leggings of a suburban Massachusetts teenager dealing with body-image issues and alienation from her peers.

“When we did our first fitting, it made me sigh [with] relief because the costumes were there and I could start to feel glimmers of Michelle,” says Fanning, who is an executive producer on both Hulu series.

Her portrayal of Michelle Carter, who was convicted in 2019 of involuntary manslaughter for encouraging “texting suicide,” as sensationalized by the media, reveals layers of a troubled 17-year-old struggling with mental health.

For authenticity, Gordon-Crozier fell into an “internet hole” studying images of Carter, circa 2014 and during the trial, and noticed that she repeatedly wore a White House Black Market puffy coat in white that previously belonged to her mother, Gail (Cara Buono). Based on the more mature labels of other pieces in Carter’s trial attire, including a floral blouse from Loft, Gordon-Crozier surmised she must have borrowed much of her courtroom wardrobe from her mom.

Turning the discovery into subtle character-building, Gordon-Crozier peppered in “little nuances” of Michelle emulating the outfits of her friends, who eventually testify against her. “She’s a bit of a lost girl and maybe didn’t really have her own sense of style,” says Gordon-Crozier.

Michelle’s adoption of her mom’s and friends’ style presented a performance-informing opportunity for Fanning. “The shell of a…