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Warning: Some spoilers ahead for Netflix’s Sirens.
The costumes in Netflix’s Sirens are have a story arc of their own.
Costume designer Caroline Duncan crafted a whole story behind the pieces the characters wear on the limited series, from the custom Lilly Pulitzer pieces to the pastel Vineyard Vines splashed across the Cliff House and beyond.
For one character in particular, her clothes speak to an evolution unlike anyone else on the show.
“With Milly’s clothing in the [Lilly] Pulitzer palette, I wanted her to feel like she’s part of this world, but she’s not actually a member of this society yet. She works for Michaela. So her costumes have to feel as if she’s following Michaela’s rules and she wants to be perfect,” Duncan says of Milly Alcock, who plays the role of Simone, the assistant to Michaela Kell (Julianne Moore).
“Part of her whole journey is letting go of this perfectionism and this mania and these panic attacks that she has throughout the miniseries have to do with her losing control when Devon shows up. So she starts in this very, very girly pink and white goop Pulitzer collaboration that we trimmed out with some extra doily features. And then the next dress she wears is one that we built from a furniture fabric to double down on the fact that she feels like one of the furnishings in Michaela’s home, that she’s been de-individualized by being a part of this posse of sycophants.”
Courtesy of Netflix ©2025
In the show, Simone comes to Cliff House — Michaela’s home that she owns with her billionaire husband, Peter Kell (Kevin Bacon), to be her assistant. It’s there on a New England island that she becomes this new version of herself that her sister, Devon (Meghann Fahy), doesn’t recognize.
In the beginning, audiences meet her as a bubbly assistant who tends to Michaela’s every beck and call, wearing brightly colored clothes to match the aesthetic. But as Duncan points out, Simone does not stand out, she is part of the staff, and like the rest of the staff — who wear mint green uniforms and are “ornamental” to match the color of the kitchen — she blends in and is treated as such.
However, as the story unfolds, Simone retreats into her old self before transforming into the true main character, overtaking Michaela herself.
Simone’s wardrobe transformation culminates in an icy blue dress that she wears for Michaela and Peter’s gala at Cliff House. It’s a floor-length gown that viewers know Michaela hand-picked for Simone to wear. What viewers don’t know is that this dress is the final shift in Simone taking Michaela’s place as the head of the household by Peter’s side.
Duncan says there was a lot of pressure to get that dress perfect, which is why she built it from scratch.
“I looked to see if I could find something that felt right for her, and the reason that I leaned into this silhouette that we ended up constructing for Milly is, she has such a fast evolution over the course of really three days. She has to completely transform from this youthful little girl into a woman. She also has to still feel like a siren,” Duncan explains.
The costume designer also wanted the color of the dress to blend with the sky as Simone was standing on the edge of the cliff in the final shot of the show because the character, in theory, now belongs in her surroundings.
“We made the dress out of a stretched satin so that it would have this ripple through the fabric and this reflective quality that echoed the clouds and the sky,” Duncan says. “It had to accomplish a lot of things, and I wanted it to fall off of one shoulder to feel draped like a Greek goddess.”
Duncan says it was also important to look at how Simone’s dress would play against Michaela’s, because the two needed to go toe to toe before Michaela made her grand exit, leaving Simone as the new lady of the house. She already had Michaela’s dress picked out — a marigold chiffon McQueen number that she says fit Moore perfectly. An icy silver blue dress felt like the right counterpoint to that.
In the end, Duncan says the dress makes the character resemble a “statue,” because Simone is a bit of a “trophy wife,” repeating a cycle for Peter. There was Jocelyn (the first wife), then Michaela and now Simone.
“She had to feel breathlessly and iconically like she fit into this cycle that may or may not continue, Duncan says. “We don’t know where her story will go.”
Sirens is streaming now on Netflix.
