Ryu Jun-yeol and Seol Kyung-gu Shine in Netflix's 'The Rat'

By Choi Songhee Posted : September 10, 2026, 17:04 Updated : September 10, 2026, 17:04
Every work has numerous perspectives. Although the director and actors share the same space and time, their experiences may differ. 'B-Cut by Choi Song-hee' focuses on the vivid behind-the-scenes records beyond the 'A-Cut' captured on screen. It reconstructs the moments of the 'B-Cut' that were more intense than the completed frames through interviews with the director and actors. (Editor’s note)

Netflix's original series 'The Rat' (directed by Kim Hong-sun) is a thriller that follows novelist Moon Jae (played by Ryu Jun-yeol), who has his name, face, and life stolen by a mysterious entity known as the rat, and loan shark No Ja (played by Seol Kyung-gu), who is trying to recover lost money. The series has climbed to the top of the global non-English shows on Netflix in its second week of release. Director Kim Hong-sun emphasized that he values the positive feedback from viewers more than the impressive viewership numbers.

"I’m very happy. In fact, 'The Rat' isn’t a work that everyone can enjoy, and there are limits to its mainstream appeal. So, I think the opinions of those who watched it are more important. If viewers found it interesting or enjoyable, then I feel satisfied," said Kim Hong-sun.

The director reflected on the challenges of portraying the dual roles of Moon Jae and the rat, noting that he believed Ryu Jun-yeol could handle the difficult role due to his performance in the film 'The Owl.'

"Watching 'The Owl,' I thought Ryu Jun-yeol could portray both roles in a way that resonated with what I had seen in the film. Initially, it was a vague thought, but I saw that potential," Kim explained.

The process of bridging the gap between the fundamentally different characters was the result of thorough and intense discussions. Up until just before filming, they kept numerous possibilities open on set to find the most convincing tone.

"It wasn’t just my direction. Ryu Jun-yeol naturally researched his character, and we discussed many cases based on his research and my thoughts. I think there were various types from one to seven or eight. We kept discussing how to approach it, and we adjusted on set. Ultimately, we concluded that 'this is the best now.' I didn’t set a strict definition for how this character should be. The actor must have had a lot of thoughts, and I would have struggled if I were in his position," Kim said.

"When expressing a character, I think it was necessary to distinguish between the external and internal aspects. I received a lot of help from the makeup team. As time went on, I could feel how detailed and dedicated the makeup team was. I prefer a natural integration rather than an overly obvious attempt. Just because it’s a genre piece, I wanted to avoid making it obvious that 'this person is playing two roles' by using exaggerated makeup. The point was to make it subtle, so that while it’s clear they are different, it’s not immediately obvious how," Ryu Jun-yeol shared.

Meanwhile, Seol Kyung-gu's character, No Ja, injects tension into the narrative with a rhythm and tone that starkly contrasts with Moon Jae. For Kim, having Seol, a veteran actor representing South Korea, was a significant asset to the project.

"Seol Kyung-gu has been an actor we’ve admired since 'Peppermint Candy.' He has already established a strong presence. When I proposed this role to him and he agreed, it felt like we had gained a significant advantage. It was like a cheat code, giving us a sense of relief that one issue was resolved. That was really important to us," Kim said.

"It was challenging to portray such a raw character after a long time. However, Director Kim Hong-sun allowed me the freedom to express myself. I was personally familiar with Ryu Jun-yeol, which made it comfortable. The director isn’t one to give detailed notes, preferring to let the actors take the lead, so I could try things my way. That could be a downside, but it was comfortable for me," Seol Kyung-gu noted.

The character of No Ja, as researched by Seol, shone even brighter when clashing with the polar opposite Moon Jae. The perfect contrast between the two characters created a powerful synergy that heightened the immersion in the story.

"I can’t do this alone. Moon Jae and No Ja are completely opposite characters. No Ja is impulsive, while Moon Jae is more laid-back. I think that contrast was well portrayed. We helped each other in embodying our characters," Seol said.

Although Ryu Jun-yeol and Seol Kyung-gu were once in the same agency, 'The Rat' marks their first deep collaboration in a project. Ryu expressed relief and excitement about finally working with his senior actor at this stage in his career.

"I’ve had a few opportunities to work with Kyung-gu for over ten years, but they never connected. I was disappointed to meet him through this project, but I also felt fortunate that it was this work. If I had met him in my early thirties, I don’t think I would have learned even a fraction of what I learned from him now. Working together now has been incredibly educational. To sum up our chemistry, it was the best. There’s an unspoken rule among actors not to dictate how to act, especially for juniors to seniors, but I shared my thoughts in almost every scene. I would say, 'I think No Ja would do this,' or 'What do you think about this?' That was possible because he was open to my ideas. Sometimes he would happily accept them, and other times he would say, 'No, you’re wrong,' but that was so enjoyable for me," Ryu Jun-yeol said.

"I wouldn’t say I contributed a lot of ideas, but Ryu Jun-yeol prepared extensively for the scenes. Usually, actors only prepare for their own parts, but Ryu considered the overall context and shared a lot. We ended up trying things out together, and if something didn’t work, we would cut it. I think we had a lot of fun doing that," Seol Kyung-gu added.

As the narrative gradually shifts into a buddy movie format in the latter half, the genuine chemistry between the two actors, developed during long waits in a confined car, is evident. Their continuous engagement with the text and each other solidified their bond both on and off the screen.




* This article has been translated by AI.

Copyright ⓒ Aju Press All rights reserved.