InterviewHow Ryu Jun-yeol tackled two roles in Netflix's series 'Mousetrap'

Korean actor Ryu Jun-yeol stepped into double-duty territory for his latest project, tackling a dual role for the first time in the Netflix original series "Mousetrap."

The psychological thriller, directed by Kim Hong-sun, follows Moon-jae (Ryu), a novelist whose identity, face and life are stolen by a mysterious figure known as "the Rat." The chase escalates as loan shark No-ja (Sul Kyung-gu) fights to recover his lost funds, while detective Sun-yong (Lee Kyu-hyung) pursues the truth.

Following its release on Aug. 28, the series quickly climbed the charts. By Sept. 1, "Mousetrap" reached No. 6 on Netflix's global TV show rankings via FlixPatrol, entering the Top 10 in 49 countries, including Korea, France, India, Singapore and the United Arab Emirates.

"I’ve been getting so many calls from people around me since the show came out," Ryu said during an interview with The Korea Times at a cafe in Seoul, Tuesday. "I can really feel the response firsthand."

Ryu admitted he was drawn to the script early on, even before the ending was finalized, curious about the fate of a man stripped of his identity. A casual conversation with acclaimed filmmaker Park Chan-wook solidified his decision to sign on.

"I happened to meet director Park Chan-wook on set, and he found the premise very intriguing, noting that the motives shouldn't simply be about money," Ryu recalled. "Seeing viewers mention 'Oldboy' now makes me feel like the story connects to themes director Park enjoys exploring."

Explaining his decision to join the project, Ryu added, "I resonated with the feelings of jealousy and inferiority in the script. They're emotions I try hard to avoid in my own daily life because they can lead to destructive outcomes. Classic epics start from very small human emotions. I was fascinated by how this story, full of raw human moments, starts from tiny emotional sparks that build up layer by layer into something massive."

To portray both the victimized novelist Moon-jae and his mysterious double, Ryu worked closely with the hair and makeup crew, prioritizing subtle realism over dramatic transformations.

"Visually, I got a lot of help from the makeup department," he began. "Even though it's a genre piece, I personally prefer subtle, natural acting that blends seamlessly into the drama rather than over-the-top characterizations."

He relied heavily on vocal changes to differentiate the two roles. "At first, the director asked what I thought about blending my voice with another actor's voice digitally," Ryu explained. "But I felt it would resonate more with the audience if I did it myself. I suggested that I alter my own voice, and the director agreed."

He delivered the Rat persona in a higher register while keeping Moon-jae grounded in his natural lower tones. "People tend to perceive my voice differently — some think it's low, while others consider it high-pitched. I knew I had a flexible range, so I thought, 'Why not use both in one project?' That's why I went with a higher tone for 'the Rat.'"

For the external look, the team kept things understated. "We wanted to avoid excessive makeup," Ryu said. "Instead, I wore contact lenses with a subtle spot for the Rat character. If you look closely, you can see the pattern, but it's the kind of detail that doesn't matter if viewers miss it — it's just a subtle touch."

Known as an actor who asks a lot of questions, Ryu shared a memorable moment working with director Kim Hong-sun.

"The director told me, 'I've never met an actor like you before. It was so much fun, and I'm really grateful.' Hearing that gave me a huge boost that will stay with me for the rest of my acting career," Ryu reflected.

"When he said that, it made me feel like I really gave this project my all, and that the director recognized my effort regardless of the final outcome. Hearing him say thank you made me feel like I’ve been on the right track as an actor."

All episodes of the Netflix original series "Mousetrap" were released on Aug. 28.