Nobody Expected Lee Sun-bin to Show Up in a Horse Costume

Lee Sun-bin had a mission to complete on the March 29 episode of MBC's hit variety show Manitto Club — deliver a birthday party invitation to her best friend Park Bo-young without getting caught. Her solution: a full horse mascot head costume, a bag of promotional wet wipes, and enough determination to charge across a public street like the racehorse she was dressed as.

The moment quickly became the most talked-about clip of the week, capturing the lengths two of Korea's most beloved actresses will go to for each other — and reminding audiences why their eight-year friendship is something fans genuinely cherish.

What Is Manitto Club — and Why Everyone Is Watching

Manitto Club (마니또 클럽) is an MBC variety series directed by Kim Tae-ho, one of Korea's most acclaimed variety producers, known for his work on long-running hits like Running Man. The show works on the concept of a "manitto" — similar to Secret Santa — where celebrity guests are secretly assigned a close friend or castmate as their target, then challenged to secretly perform a meaningful surprise for that person.

The third generation of the show's cast, which joined in Episode 8, includes Cha Tae-hyun, Park Bo-young, Lee Sun-bin, Hwang Kwang-hee, and Kang Hoon. The previous episode hit a series-high 2.6% viewership rating in the Seoul metro area, signaling that the new lineup has struck a chord with viewers. Episode 9, which aired on March 29 at 6:05 PM KST, featured each of the five new members completing their individual manitto missions.

The Horse Costume Plan: Lee Sun-bin Goes Undercover

Lee Sun-bin's assigned manitto was Park Bo-young — her close friend of eight years. The task was deceptively simple: plan a surprise pre-birthday party and deliver a written invitation without revealing who sent it. Knowing that Park Bo-young knows her face better than almost anyone, Lee Sun-bin devised a disguise that relied on hiding it entirely.

Her chosen method was a horse mascot head costume. Positioning herself on a busy street under the guise of a promotional part-time worker handing out wet wipes to passersby, Lee Sun-bin waited for Park Bo-young to appear. The moment she spotted her target, she launched herself across the pavement, the preview footage showing her making full contact with Park Bo-young in what one outlet described as charging "like a racehorse."

It almost fell apart immediately. Park Bo-young's instincts kicked in — she looked at the costumed figure in front of her, appeared to read the situation, and the expression on her face suggested she was on the verge of asking the one question Lee Sun-bin could not answer honestly. Lee Sun-bin described her own feelings in the moment as "너무 떨린다" — roughly, "I was shaking so badly."

Her recovery was swift and creative. Rather than breaking cover, Lee Sun-bin doubled down: she acted as if she had been sent by a third party, using over-the-top hand gestures to redirect attention and create just enough confusion for Park Bo-young to accept the invitation without pressing further. Park Bo-young, reading the formal and slightly stiff tone of the letter, landed on a conclusion: "진짜 MBTI I이신 것 같아" — "Whoever wrote this seems like a real introvert." The comedy of that assessment, given what viewers knew about the theatrical extrovert standing in front of her, was not lost on anyone watching.

An Eight-Year Friendship in the Spotlight

Lee Sun-bin and Park Bo-young are close friends in real life — a fact that adds a layer of meaning to the episode that might be lost on viewers unfamiliar with their relationship. The two have known each other for eight years, and their dynamic has occasionally surfaced in public view: Park Bo-young has visited Lee Sun-bin on set, and the two have been photographed supporting each other at events and quietly showing up for one another in the way longtime friends do.

Park Bo-young, born in 1990, has been one of Korea's most consistent leading actresses for nearly two decades. Her career includes the blockbuster film Scandal Makers (2008), the beloved fantasy drama Strong Girl Bong-soon (2017), and more recently, the critically praised Netflix series Daily Dose of Sunshine (2023). Her 2025 project Our Unwritten Seoul, in which she played dual roles as identical twins, broke domestic cable ratings records. She is frequently described by fans as "국민 여동생" — the Nation's Little Sister — a reference to the warmth and approachability that have defined her public persona throughout her career.

Lee Sun-bin, born in 1994, made her name in dramas like Work Later, Drink Now on TVING, a show that ran across multiple seasons and became a cultural touchstone for young working women in Korea. Off screen, she has been in a relationship with actor Lee Kwang-soo since 2018, making them one of the most openly affectionate celebrity couples in the industry. Kwang-soo, who rose to fame through years as a cast member of Running Man, addressed the relationship directly in a 2025 interview: "We won't break up." It is a line that has become something of a personal motto for the couple.

Why This Moment Resonated Beyond the Episode

The preview clip — released ahead of the broadcast — circulated quickly across Korean entertainment social media. The visual of Lee Sun-bin running in a horse costume, the comedic near-miss where Park Bo-young almost figured it out, and the punchline of the "introvert" read all hit in quick succession, giving the clip the kind of compact, shareable energy that drives variety show buzz.

But underneath the humor, there is something more straightforward at work. Viewers have watched Park Bo-young and Lee Sun-bin build careers separately for years, and seeing the two interact in an unscripted context — even a carefully produced one — offers a glimpse of the relationship behind the public personas. The fact that Lee Sun-bin was willing to stand on a street in a horse costume, maintain cover under pressure, and go through genuine real part-time work to sell the disguise, says something specific about how far she would go for someone she cares about.

As for the birthday party itself — whether the mission succeeded, whether Park Bo-young finally put it all together, and how the surprise played out — that became the reason to tune in on Sunday evening.

What's Next for Both Actresses

Lee Sun-bin is currently attached to an upcoming period action film, The Sword: Legend of the Red Wolf (2026), alongside Park Bo-gum and Joo Won, which is expected to be one of the year's more anticipated theatrical releases. Her continued balance between drama, film, and variety appearances — plus a relationship that remains one of the more stable in the Korean entertainment industry — has kept her in steady public conversation even outside of active promotional periods.

Park Bo-young, for her part, has shown no signs of slowing down after a banner year in 2025. The conclusion of Our Unwritten Seoul left fans immediately speculating about her next project, and her presence on Manitto Club has been warmly received as a chance for audiences to see her in a less scripted setting than the roles she typically plays.

For now, the horse costume is the story. But it is also, in a smaller way, a reminder of the friendships that exist behind the carefully managed public images of Korean entertainment — and why those glimpses, when they appear, tend to mean something to the people watching.