Actress Kim Yoo Jung wanted to show a darker side of herself in the film "Circle of Atonement" and it wasn't easy.

At an October 13 press conference for the film, she spoke about the difficulties in portraying the character Lee Jung Hyun. It was not an easy role to get into and it was not an easy one to recover from.

"After filming the movie, I had a hard time," said Kim. "Honestly, while we were filming I did not feel as if I had become immersed in the character. I had fun filming with senior Sung Dong Il, so I had not thought that much about it. After I stuffed the emotions in, they gradually started to come up. My encounter with those feelings was delayed so I had a hard time."

The director Lee Dong Ha said he was pleasantly surprised by her focus.

At an October 7 press conference, Kim spoke about her reason for taking the role.

"I haven't had a chance to play characters with deep internal stories, which is why I really wanted to do this movie," said Kim. "Through this role I wanted to show a darker side of myself."

Her character may seem cheerful on the surface but she is tortured by secrets. To create that dark and lonely character, Kim said that she spent a lot of her free time alone.

The mystery film concerns three characters. Son Ho Joon plays Nam Chul Woong, a man whose fiancee was murdered. Sung Dong Il plays Detective Lee Sang Won, the detective on the case. Kim plays Lee Jung Hyun, the murderer's daughter. The detective adopts the murderer's daughter and raises her. Eleven years later, Lee Jong Hyun, now a high school student, winds up in a class taught by Nam Chul Woong.

One of the best known child actresses in Korea, Kim made her debut in a TV commercial at the age of 4. She appeared in such dramas as "The Moon Embracing The Sun," "May Queen," "Golden Rainbow" and "Secret Door." Her most recent drama role was playing Kim Hee Sun's bullied daughter in "Angry Mom." She received praise for her role in the film "Thread of Lies" and this year can also be seen in the film "Because I Love You."

The film, which also stars Seo Ye Ji, premiered at the Busan International Film Festival on October 2 and will be in theaters on October 15.