The actor’s death was announced in a statement released by her agency, Landscape, but no cause of death was disclosed.
“Kim suddenly left us on Jan 5,” said the statement.
“The bereaved are deep in their sorrow at the sudden sadness. Please refrain from reporting false rumours or speculation so that the family can mourn in peace.”
The statement was obtained by Variety and has been translated from Korean.
Kim played a student and activist called Yeo Jung-min in the South Korean TV series Snowdrop. Her character shared a women’s dorm room with Eun Young-ro, portrayed by K-pop singer Jisoo.
The romantic drama is set against the backdrop of the 1987 pro-democracy movement. It has sparked much controversy over its historical accuracy, choice of songs and depiction of North Korean people.
A petition to stop the programme airing has gathered over 300,000 signatures.
Responding to the growing backlash against the series, some sponsors have asked to terminate their deals with the production company.
Kim’s other credits include Hi Bye, Mama!, Into the Ring, The School Nurse Files, Lipstick Revolution and Kyungmi’s World.
She had also recently begun filming another Disney Plus drama, Kiss Six Sense.