Yim Si-wan in Love in Disguise: why an old K-drama trick feels new

02Yoon Yi-jun, the heir nobody can read

Yim Si-wan plays Yoon Yi-jun, the third-generation heir of the Taegang Group. His former secretary is found dead, and suddenly he is the prime suspect. His answer is to shut the whole world out.

Many viewers know the actor from Squid Game, but his acting goes back fourteen years, to Misaeng. For this role, he said he focused on one thing: how Yi-jun hides his feelings. He built the character in layers, so it is never quite clear when Yi-jun is being sincere. Polite on the surface, perfect even, and underneath, impossible to read. He also already has a fiancée, the art center director Lee Si-a. So the question hangs over every scene: is he guilty, or hiding something else?

03Kang Jae-hee, the detective who protects him

Seol In-ah plays Kang Jae-hee, a detective who once served in the special forces. Her mission is to get inside Yi-jun's world, and the only door in is a job as his secretary and bodyguard. That job is meant for a man, so Jae-hee goes undercover as one.

For the role, Seol In-ah cut her hair short. She admitted it felt strange and hard at first. Then, slowly, it became a chance to discover something new about herself, and in the end the short hair stopped being a costume and became part of Jae-hee. Viewers of Mister Queen or Business Proposal already know her, but this is her first full gender-bending rom-com.

The best part of the setup is the reversal. She is the trained soldier, so she is the one who protects him. One of tvN's teasers even calls her his knight in shining armor.

04Coffee Prince, a year of casting and a bromance

Chief producer Kim Ho-jun pointed to Go Eun-chan, the heroine of Coffee Prince from 2007, as the kind of lead the team hoped to create. He also said they spent almost a year trying to cast Yim Si-wan. The goal was a romantic lead unlike anything viewers had seen before.

Here is the twist that drives the story: Yi-jun starts to fall for his new secretary while believing the secretary is a man.

So the comedy comes from what he doesn't know, and the ache comes from what she can't say.

Yim Si-wan called it his first story built around a bromance, and a fresh creative challenge. To find his way in, he went back to The Merciless, his 2017 film. Director Park Dan-hee says none of the main characters fit the usual molds, and describes it as a story about two people with old wounds who end up comforting each other. And under all of it, there is still a murder case, so every sweet moment stays a little tense.

05From Kakao Page to Monday nights

The story began as a web novel and webtoon on Kakao Page. Its original title asks, almost cheekily, why nobody can tell that she is a woman. Filming ran from December 2025 to June 2026, so every episode was shot before the first one aired.

On television, the premiere's 5.6 percent was followed by 4.7 percent for episode two. The drama took over the slot from The Ordinary Jackpot, whose finale had reached 6.2 percent, so the bar was high. Even with that dip, it stayed number one in its time slot across all cable channels.

And keep an eye on a second couple. Kim Jung-hyun plays Yi-jun's best friend, a lawyer on the group's legal team, and Yeonwoo plays the chairman's secretary. Love in Disguise runs for twelve episodes, every Monday and Tuesday on tvN, until November 24, and in many countries new episodes stream on Prime Video.

06So who is truly guilty?

The old trick feels new because here the disguise is not just a joke; it is part of a murder investigation. Both leads are hiding something, and both are watching each other. Yim Si-wan has said that Yi-jun begins to change after he meets Jae-hee, and that change is the part most worth waiting for.

Even the Korean title means My Guilty Human. So maybe the real question is not who did it, but who is truly guilty here: the heir everyone suspects, or the detective who lies to him every single day?