SEOUL – Negative 100 per cent – that is what South Korean actress Kim Yoo-jung said at CGV Yongsan in Seoul on Oct 30 when asked about her sync rate with her latest character Baek Ah-jin.

“I got so swept up playing her that I barely checked the monitor. But that’s obviously not who I am.”

Kim, 26, had just spent the better part of the press conference explaining how she plays a top actress who, wearing a mask of perfection, crushes anyone standing in her way in the new K-drama Dear X. Based on a hit webtoon of the same title, the thriller series premieres on HBO Max on Nov 6.

The distance might be what sells it. For someone who has built a career playing upright, feel-good characters – think Love In The Moonlight (2016) and Lovers Of The Red Sky (2021) — since her days as a beloved child actress two decades ago, taking on a ruthless sociopath is an entirely different sport.

Ah-jin claws her way to stardom by leaving behind a trail of broken people – the “Xs” of the title. She has two enablers in her orbit: childhood friend Jun-seo (Kim Young-dae), who is convinced he can pull her back from the edge, and Jae-oh (Kim Do-hoon), who follows her around like a true believer.

Dear X adds original material to the webtoon’s four-part structure, but the core premise stays intact. It is the kind of character study that taps anxieties about the celebrity machine – how much darkness can someone bury under the movie-star glamour?

Kim explained her approach without overthinking it. “I tried not to see this as some huge challenge. If I’d thought about the pressure, I would’ve tensed up.”

She turned to the source material; the webtoon’s static format helped capture the character’s essence. “The images are frozen, so you get these unreadable expressions. I focused on stripping things away, lots of scenes where it plays through the eyes. You’re supposed to feel that mystery.”

Director Lee Eung-bok, a veteran whose credits include Sweet Home ...