Kim Hye-yoon, for once, dials it down

Remember that wide-eyed, time-hopping superfan who willed her dead K-pop idol back to life in the 2024 megahit "Lovely Runner"? The one who flailed and fussed and flung herself across decades for a boy too cute to stay buried?

That girl just waded into a haunted reservoir and isn't coming back the same.

"Lovely Runner" is probably best remembered for minting Byeon Woo-seok — all impossible good looks and camera-ready proportions — into an overnight sensation. But the girl opposite him held up her end of the bargain, her hyper-expressive, pitch-shifting brand of acting hitting the sweet spot for the rom-com-fantasy faithful.

That performance all but branded Kim as the face of Korean drama's fairy-tale chickflick circuit. The general take is that she's the kind of lead who can sell a premise built on supernatural gimmickry while keeping the whole thing breezy. She's doubled down on the mold with this year's "No Tail to Tell," playing a shapeshifting nine-tailed fox from Korean folklore.

"When a previous project gets so much love, you've got this pressure," Kim said on Thursday at a cafe in Samcheong-dong, central Seoul. "So many people showed me that love, and I feel like I owe them something different that they haven't seen yet."

That sense of pressure goes some way toward explaining her detour into "Salmokji: Whispering Water." The upcoming horror film follows a road-view mapping crew dispatched to a remote reservoir to reshoot footage marred by an unidentified figure. Kim plays Soo-in, the team leader who steps in after a colleague who previously visited the site went missing.

As it turns out, horror is the genre closest to the actor's heart. "I've always been a horror junkie," Kim says. "I was already familiar with the camera setups and the gear, so I could get into the technical side of things with the director in a way I hadn't before." Director Lee Sang-min, making his feature debut after a string of horror shorts, shared the obsession; the two bonded over the genre's craft off-set.

Kim frequently catches herself mid-answer, doubles back, asks whether what she's just said offers anything new. You get the sense of someone dead set on making every answer count.

Asked what keeps her going, she circles back to a metaphor she clearly holds close. "I think of each project as a diary entry," she says. "The expressions I'm capable of right now, the depth I can bring at this moment, they only happen once. So I try to put it all in, like I'm writing it down for myself."

It's not as if she's been boxed into rom-coms, though. What often gets lost is the range she's already put on the table: Look no further than her raging, nasty villain in "Sky Castle," or the vengeance-fueled teen she anchored a whole feature around in "The Girl on a Bulldozer."

But the bottom line is that the same DNA runs through all of it: a full-throttle, camp-adjacent intensity that ties her lovesick heroines and fiery antagonists into the same fabric. Some actors revel in restraint; Kim has never been particularly known for it.

That's precisely what makes her work in "Salmokji" cut deeper than a mere genre switch. As horror-film heroines go, her Soo-in is an anomaly — no screaming, no spiraling, little by way of theatrics. She's the one who keeps her head while everyone else falls apart, the last person in the room still trying to think straight amid all the madness.

"I think what I learned on this one was how to hold back," Kim says. "I tried to distance myself from the energy and brightness that come naturally to me. The fear, the urgency, I tried to keep it all in the eyes."

"I love acting, but I'm tormented by how much I still can't do. Some of my colleagues were making their screen debut this time, and watching them throw themselves in so seriously — that's what kept me going."

For now, she's still figuring out the balance between preparation and instinct. "I used to want to show up a hundred percent ready. But there are things you can only get from being on set in the costume and the space. It fills in the rest."

As for what's next: Kim is currently shooting a full-blown comedy, her first crack at the genre. "With 'Salmokji' it was all about how to be scarier. Now it's about how to be funnier," she says. "Which, honestly, might be harder."

"Salmokji: Whispering Water" opens April 8.