Actress Park Bo-young, who plays identical twins Mi-ji and Mi-rae in tvN’s TV series "Our Unwritten Seoul," which concluded on June 29. Courtesy of BH Entertainment

tvN’s TV series "Our Unwritten Seoul" follows the story of identical twins Mi-ji and Mi-rae, who briefly swap lives and experience each other’s world. Mi-ji, once a promising track athlete with a cheerful personality, remains simple and upbeat even in her 30s. Mi-rae, who spent much of her childhood in hospitals due to a congenital heart condition, has grown into a reserved office worker in Seoul who keeps her emotions guarded.

The series, which aired its final episode on June 29 receiving positive reviews, featured actress Park Bo-young, 35, in the dual roles of Mi-ji and Mi-rae. From the bubbly Mi-ji to the emotionally dry Mi-rae, and even the scenes where they impersonate each other, Park delicately portrayed a story that was almost like playing four roles in one. Her performance helped the finale, Episode 12, reach the show’s highest rating yet of 8.4 percent.

“It was such a touching and comforting script that I worried someone else might take the role. I thought, ‘I need to get in line for this one,’” Park said during an interview at her management agency in Gangnam District, Seoul, on June 26. “Only after accepting the role did the anxiety about playing two characters hit me.”

Park took care not to exaggerate the differences between the twins, instead offering subtle hints to allow the audience to detect their identities. This approach aligned with the director’s request: “Even if they appear to be the same person, don’t use a tone you normally wouldn’t use.” When portraying Mi-ji, Park drew from her own cheerful demeanor in social settings, while for Mi-rae, she drew on her quieter, more introspective side seen in private or with family.

Park even saw reflections of herself in Mi-ji. While Mi-ji seems cheerful enough to be called “Candy” in her hometown, she had actually spent years as a recluse after an injury in high school shattered her dreams of becoming a professional athlete. It is not revealed until about a third of the way into the show that Mi-ji had stayed indoors for over three years.

“I saw my past self in Mi-ji, someone who was emotionally struggling but still trying to seem fine and cheerful,” Park said. Playing Mi-ji, who rarely leaves the house, required imagination, but Park said she drew on memories of times when she had emotionally shut herself off from the world.

“Even if not for three whole years, we all have days when we don’t want to see anyone,” she said. “It’s a familiar kind of emotion. And because this story encourages people to step outside, I tried to focus on Mi-ji’s growth.”

Though Park previously played a pseudo-dual role in "Oh My Ghost,” where her character is possessed by a ghost with a contrasting personality, "Our Unwritten Seoul" posed a fresh challenge with scenes where both twins appear simultaneously. More than filming the same scene twice, the hardest part was making eye contact with an imaginary version of herself. While she had a body double, she often had to act into empty space during reshoots. “This TV series made me feel like I leveled up,” she said with a smile.

Working alongside seasoned actresses like Won Mi-kyung, Jang Young-nam, and Cha Mi-kyung was also a memorable experience. “I could feel how the senior actresses held the production steady from both sides,” she said. Often, instead of sticking to rehearsed lines, Park found herself reacting spontaneously to their performances. “That felt much better,” she said.

"Our Unwritten Seoul" features a cast of characters with visible or hidden vulnerabilities, including the male lead Ho-soo (played by Park Jin-young), who lost hearing in one ear due to a car accident. “Our show features many characters considered to be minorities,” Park explained. “I think a lot of people found someone they could identify with, and that’s why it resonated.”

The thirty-something protagonists of the series often blame themselves and drift through life. Park, now in her 20th year as an actress, admitted she experienced similar struggles. “As a rookie, whenever I was scolded by a director, I thought, ‘Maybe I’m not cut out for this. Should I do something else?’ Even when I first got a lead role, I wondered if I was ready for the responsibility.”

In the TV series, Mi-ji says, “It feels like I don’t belong anywhere,” to which Ho-soo replies, “Wherever you are, that’s your place.” Park said she now agrees with that line. “Looking back, I think wherever I was, that really was my place.”

Park also highlighted a memorable line from the twins’ grandmother, Wol-soon (played by Cha Mi-kyung), saying, “Anything you do to stay alive is an act of bravery.” She added, “Everyone goes through times they consider ‘failures.’ She said she especially liked Wol-soon’s words, which reminded her that the choices we later regret were, at the time, the best we could make.

As she bids farewell to Mi-ji and Mi-rae, Park expresses her gratitude to viewers. “Looking back, many things that felt like major failures weren’t so big after all. But at the time, it can feel like you’ll never move forward. I hope this series, which includes both people who say ‘that’s not true’ and those who simply endure quietly by one’s side, has been a source of comfort to anyone going through such times.”