Actor Kim Nam-gil, who stars in actor Jung Woo-sung’s directorial debut film, “A Man of Reason,” said working with Jung was not “an easy choice,” despite his close friendship with one of the country’s top actors.

"To be honest, I had decided to avoid doing projects with actors-turned-directors because they know acting too well and there is no way for me to escape. Jung knows about acting very well and has accumulated expertise in working with actors. That was really helpful when communicating as actor and director, but because he is such a good actor, shooting was tough for me on the other hand,” Kim told The Korea Herald in an interview on Aug. 10.

"Of course, if he chooses to cast me in his upcoming projects, I would be more than willing to star in them," Kim said with a laugh.

“A Man of Reason” follows the story of Soo-hyuk (played by Jung), who has spent 10 years in prison in place of his gangster boss, Eung-gook (Park Sung-woong). After he is released, Soo-hyuk tells Eung-gook that he wants to leave the gang and live an ordinary life after discovering that he has a daughter.

Kim plays Woo-jin, a contract killer who never misses his target. In the story, he is given the mission to assassinate Soo-hyuk. Woo-jin has a playful personality but is cold-hearted and bloodthirsty at the same time, showing two distinct, extreme characters.

One example is when he shoots Soo-hyuk in front of his daughter with a self-made nail gun. When he is caught by the apartment building guard, he simply flees the scene, saying, “Oh, we were just in the middle of a play gunfight.”

“It’s not an exaggeration that the character was not an easy one to portray and it was hard to find the balance in acting. What I focused on was that even for this kind of dark, noir action film, there should be a character that has breathing room to be both familiar and entertaining. I interpreted Woo-jin’s role to be that, which director Jung also agreed to,” Kim said.

Director Jung told reporters during a press conference prior to the movie opening that he picked Kim to play Woo-jin as Kim's real personality is similar to Woo-jin’s bright, cheerful character.

“When I worried that Woo-jin’s liveliness would hamper the film’s weighty message, director Jung told me to trust him in terms of keeping the balance in the movie,” Kim said.

“The Jung Woo-sung I know as a close friend and the Jung Woo-sung I know as a director were similar. He has respect and a sincere attitude toward the people he works with. He must have been super-busy both directing and acting as one of the protagonists of this movie, but he never forgot to let the actors freely express their feelings through their characters,” said Kim.

“A Man of Reason” opened in local theaters on Aug. 15.