Arin undergoes dramatic physical and emotional transformation for her role in the adult thriller S-Line The idol-turned-actress discusses filming intimate scenes Her bold performance marks a complete departure from Oh My Girl's innocent youngest member image
From her debut as the youngest member of the beloved K-pop group Oh My Girl to her growing reputation as a daring actress, Arin has continuously defied expectations in the most compelling ways. Her latest role in the provocative fantasy thriller S-Line marks her most audacious transformation yet—both in terms of character depth and on-screen boldness.
Based on the popular and risqué webtoon by Kkomabi, S-Line delves into the dark undercurrents of human relationships, exploring forbidden desires and hidden truths through a supernatural lens: a mysterious red line (the "S-Line") appears between people who have had sexual relationships. The series has already made significant waves since its premiere, topping Wave’s paid subscription charts for an impressive 14 consecutive days and even securing the prestigious Best Music award at the 8th Cannes International Series Festival—a testament to its gripping storytelling and haunting atmosphere.
Breaking Free from Innocence: Arin’s Immersion into the Complex Role of Hyun-heup
Source: IMDb
Arin takes on the role of Hyun-heup, a high school student burdened with the unsettling ability to see these S-lines—a power that isolates her from others and forces her to confront the hidden intimacies of those around her. Unlike her previous roles in romantic dramas like Hwanhon: Light and Shadow and the coming-of-age film Summer, Love Machine Blues, this character demanded a stark departure from her usual bright, youthful image—one that fans had associated with her for nearly a decade as Oh My Girl’s beloved maknae.
"The genre itself has some unconventional aspects. When I first received the script, it was so different from what I’ve done before. I worried whether I could pull it off naturally," Arin admitted in a candid interview, quoted by Chosun July 28.
The psychological depth of Hyun-heup required Arin to tap into emotions far removed from her idol persona. Hyun-heup is introverted, burdened by her supernatural ability, and emotionally detached—a far cry from the cheerful, energetic performer fans were used to seeing on stage.
To fully embody her character, Arin underwent a striking physical and mental transformation. She chopped her hair into a short, boyish cut—a dramatic shift from the long, flowing locks she often sported with Oh My Girl. She minimized her makeup, opting for a bare-faced, almost sickly pallor to emphasize Hyun-heup’s reclusive nature.
"I even left my eyebrows undone and added faint freckles to make her look more unkempt. Hyun-heup doesn’t go out much, so I wanted her to look unpolished, almost fragile. Her appearance had to reflect her loneliness,” Arin revealed.
The emotional weight of the role was equally challenging. "Hyun-heup is special yet deeply pained. She’s lonely because her ability pushes people away," Arin explained. "I had to convey that quiet suffering without overacting—letting the audience feel her isolation through subtle expressions rather than dramatic outbursts." Her meticulous efforts paid off—fans and critics alike were stunned by her unrecognizable performance. "People said they couldn’t believe it was me. That reaction was so rewarding," she shared with a smile.
From Beloved Maknae to Mature Actress: Shattering Expectations and Winning Support
Source: IMDb
For nearly a decade, Arin was synonymous with Oh My Girl’s innocent, youthful image, making her S-Line role all the more shocking to longtime fans. Yet, rather than meeting resistance, she found overwhelming support from her fellow members.
"They understood when I was quieter than usual during filming. Hyun-heup’s personality even bled into my daily life at times, but my members would say, ‘Arin is focused right now,’ and gave me space,” she shared.
Their reaction after watching the drama was even more heartening. This encouragement was crucial for Arin, who was stepping into uncharted territory not just as an actress but as a public figure breaking away from a carefully cultivated image.
"They told me, ‘This side of Arin is really attractive’. They were surprised at first, but they also enjoyed seeing me in such a different light." she recalled.
The drama’s mature themes, including a pivotal and intimate scene in the latter half of the series, further cemented her departure from her idol roots. Arin approached the scene with utmost professionalism, emphasizing its narrative necessity rather than sensationalism.
"It was crucial for the story. The director and I discussed at length how to make it feel natural for Hyun-heup and her partner," she explained.
While some fans were initially taken aback, many ultimately praised her commitment to the role.
"I’m grateful people saw this as my first real step toward becoming ‘actress Arin,’ not just ‘Oh My Girl’s Arin.’"
No Limits: Arin’s Expanding Ambitions Beyond the Screen
Source: IMDb
Arin’s thirst for challenging roles doesn’t stop with S-Line. A self-proclaimed noir enthusiast, she dreams of tackling gritty, high-stakes action films like The Thieves and New World.
"I’ve always loved intense, dark genres. I’m preparing hard—physically and emotionally—so I can play a cool, refreshingly bold character someday," she revealed.
Her willingness to experiment knows no bounds. When asked how far she would go for a role, she didn’t hesitate. This fearless mindset extends to her long-term aspirations in acting.
"If a character demanded it, I’d even shave my head. I want to try everything—no restrictions.My ultimate goal is to make people forget ‘Arin’ entirely when they see me on screen. I want them to only see the character. I want to be an actress with no limits,” Arin Concluded.
With S-Line, she has already proven her fearlessness—and this is just the beginning. As she continues to push boundaries, one thing is certain: Arin is no longer just the "youngest member" of Oh My Girl. She is a formidable actress, unafraid to challenge norms and redefine herself. And if her trajectory so far is any indication, her most groundbreaking performances are still ahead.
Check out Arin in the S-Line trailer!
The emotional depth in Arin’s eyes! Reminds me of young Natalie Portman in Black Swan. Anyone know the streaming platform?
Where’s everyone watching this? Need to see Arin’s acting chops right now! Platform pleaseee~
From cute maknae to this bold role?? So proud but also shocked! Still remember her in Nonstop days 
How do other Miracles feel about this? 
I stayed up all night reading the webtoon after watching ep1! The way they visualize the S-lines is so creative?? And Arin unnie acting her heart out?? We love a versatile queen!