Unlike other movies that feature a major evolution for a young female character—think The Princess Diaries or She's All That—costume designer Jessica Flaherty stressed how "important" it was to her and author Jenny Han to "not allow the clothes to get ahead of her transformation."
"I always picture what did Belly pack to bring to Cousins from her wardrobe," Flaherty continued. "So, the first few episodes, we kept her in her shorts and her big t-shirts she might have slept in."
As the season progressed and the character's world starting opening up, she would have "pops of her fish-of-water moments," as Flaherty described them. Belly was trying to figure out what she liked sartorially while her mother figure Susannah (Rachel Blanchard) and her best friend Taylor (Rain Spencer) were also picking items out for her.
"It was her finding her way within all these new pieces and influences in her life," Flaherty said. "So it wasn't like, 'Oh, Taylor got me that pink dress, I'm going to go there.' She's like, "That's not quite it, but I could try a dress,' and then we land on a gingham one."
Not wanting to "rush that evolution," Flaherty said she used relatable and subtle shifts in Belly's style, like choosing a two-piece bathing suit over a one-piece, "because those beats are really important in a girl's life when you are also trying to find yourself."
"It's Belly opening up a little bit more and taking chances," she added. "And it was so nice to do that in a gentle, organic way that we got her to the coming out at the debutante ball."
"It's just one dress, but it's the dress!"
That was Flaherty's thought process for dressing that epic event in the finale, noting that the most important task was finding the perfect look for Belly. While Flaherty initially envisioned designing Belly's look, once she learned Han's vision for it, she admitted, "It was just so beautiful and perfect in telling the story of what Jenny wanted to tell, where Belly picks this dress of all of them, despite the other one being purchased and chosen for her."
But Flaherty definitely felt the pressure to make that vision a reality, especially after the initial dress they had their hearts set on fell through.
"We need to have multiples, so we have this dress that we could not multiply and it was also really had to get," Flaherty explained. "It was in the U.K., so just getting the sizes and shipping was crazy and we were coming out of COVID, so it was still difficult to guarantee you could get it."
After a weeks-long search, they finally found another dress—a wedding gown from overseas—which two tailors were able to make several copies of.
But Belly was just one of hundreds of people that needed to be dressed for the formal event, with Flaherty admitting, "There was definitely a moment where I was like, 'Can we pull this off?' It was a challenge, but it was a fun challenge."
Of the series' three main male characters, the eldest Fisher brother cared the least about his style, according to Flaherty.
"He not a clothes guy," she reasoned of the brooding Conrad. "He probably wears whatever he pulls out of a dresser drawer that his mom put in there." Given that he was a football player, Flaherty opted for polos, shorts and hoodies that are simple but also played into that "Abercrombie, all-American boy that we wanted to do without the branding," she said.
While his big bro is all about comfort and ease, the fun-loving Jeremiah is willing to get playful with his wardrobe—within reason. Flaherty opted for AllSaints clothing for Jer, with printed button downs serving as his staple piece, which would be paired with something more casual, like a pair of Vans sneakers.
"We found a lot of fun things to do with him, but he was still also not too hip," Flaherty said. "He was less afraid to play around, so prints and it was really fun to have this handsome All-American boy but do pops of fashion and still keep it within our world of dreamy, chill summer vibes."
A small-but-key book about Belly's older brother from the first book that became Flaherty's "guiding force" for the character was that he saved up $400 to buy the sunglasses he wears all the time and cherishes.
"Their family is from a certain economic background, but he's into streetwear," Flaherty said. "So we had to be careful how hard we went with it because it's expensive. I like to think of Steven as having certain pieces that were really special to him, whether it's his sneakers or a certain pair of pants and those are the things that we imagined he would spend his money on."
While Steven's style was cooler than Conrad and Jeremiah's, Flaherty said it was a "delicate balance" to make sure he still fit into the world.
"You don't want the clothes to ever be louder than what we're doing," she reasoned. "It was actually challenging in a good way to find things that someone his age would realistically be buying rather than just lacing him up in $800 sneakers."
For the show's matriarchs, who have been best friends for decades, Flaherty wanted to express their individual personalities through their clothing.
"Susannah was more '60s- and '70s-inspired, so we were able to have a little bit more fun with color and print," Flaherty explained of Conrad and Jeremiah's mother. "She had pinks and softer colors. She really wasn't afraid to play with whatever palette and print."
Belly's mom, however, was all about "form and function," Flaherty countered, which played into Laurel's career as a novelist.
"It's never messy, it's totally chic and put together, but not thought about," she said. "Her color palette is black, cream, navy and taupe. I love a chic, classic Diane Keaton look. She had a very east coast vibe."
For Belly's sweet first boyfriend, played by David Iacono, Flaherty was excited to infuse a slightly more alternative style into the beachy world of Cousins. But she opted to "marry" the idea of Supreme Skate Team in the '90s with the more modern skateboarder look. But there was one unexpected challenge when Flaherty was attempting to dress Cam in long sleeve shirts and baggier pants.
"It's so hot and there were times where I wanted to keep him in those big jeans the whole time," Flaherty said,"but then you go, 'Well, he's a kid, he can wear shorts, this is normal in summer to also change it up.'"
And even though Cam's style was more punk than the other boys, Flaherty stressed that she "wanted him to look sweet and youthful as well."
If you thought the show looked like it was filmed in the Paris filter on Instagram, filled with soft shades and dreamy fabrics, that was Flaherty's intention.
"It's not a fantasy, but it's this summer place they look forward to every year," Flaherty said. "It's the beach, it's soft and it's untouched by the harsh realities and garishness of high school. It's very different than other shows that represent high school kids, where things are a bit sharper and brighter."
To achieve that look for Belly, Flaherty opted for softer colors, including buttercup yellow and peach, and touched of patterns, including gingham and light florals.
While the ladies of Outer Banks may be running around in crop tops and bikinis, Belly favored oversized t-shirts, something Flaherty picked up when she arrived in North Carolina prior to filming.
"Being based in L.A., I didn't see that new sports look," Flaherty said. "As soon as I landed, I saw it everywhere and that was my big research. It's very different in L.A. how 16-year-old girls dress, so I was like, 'Is it realistic for me to be doing this big t-shirt thing as a normal look?' And it was unbelievable, the second I stepped foot in Target in North Carolina, I was like, 'Wow, this was all the research I wish I had before I got here.'"
Some of Flaherty's pop culture touchstones for the show included TV shows and movies from the '90s, including My So-Called Life, Stealing Beauty and Dirty Dancing, which she paid homage to with Keds sneakers, shorts and tank tops. "I'm a '90s kid, so those really spoke to me," Flaherty explained.
But there was also a surprisingly modern source of inspiration as well: The Hulu limited series Normal People, with Flaherty gushing, "There was something really beautiful about the costumes on that show, the mood and feel."
For Flaherty, being part of The Summer I Turned Pretty was a life-altering moment, one she almost passed on as she had plans to celebrate her birthday abroad.
But after meeting with Han, "I went from being so excited to go to Europe to really hoping this would work because I had never gelled in mood and vibe like that before," Flaherty said, explaining that the mood boards they each had created were very similar. "I was like, 'Oh my god, this is the best thing that's ever happened!' In my entire career, I had not had that sweet spot."
And it got sweeter from there, with Flaherty and Han working hand-in-hand to bring Cousins to life.
"I came into it by happenstance but it was the best happenstance," Flaherty admitted. "It was one of those moments in your life where you say, 'Oh wow, this is a changing moment for me.' I'm so proud to be a part of creating this world."