Working with actress Jeon Do Yeon in the film "Shameless," was a challenge, said Kim Nam Gil, and he did not always feel like he was up to speed. When he saw the movie for the first time he was impressed by her acting and realized why she invites praise.

"I was stunned when I first saw the movie," he said in an interview with the Korean media outlet Star Today. "Then I realized what the fuss about Jeon Do Yeon was all about."

He said he wished he had done a better job.

"She's been at this for 24 years while it has only been 10 years for me. I have a lot of catching up to do."

According to Kim, Jeon Do Yeon quickly mastered the emotional scenes in a way that made him feel as if he was trying to catch up.

"She went at about 135 kilometers (83 miles) per hour," he said. "I didn't know what to make of the scenes so we talked with each other. But then when I saw the movie, I had to admit it right away. I am only just beginning. It's always the beginning for me."

The 42-year-old veteran actress has not done a drama since the 2008 "On Air" but has appeared in a few memorable films since then. This year she can also be seen in the film "Memories of the Sword" with Lee Byung Hun. She attended the Cannes Film Festival with Kim Nam Gil this year to promote "Shameless" but it was her second invitation. She also attended the festival in 2007 because of her role in "Secret Sunshine."

In "Shameless," Kim Nam Gil plays a jaded detective named Jung Jae Gon. He's trying to find a mob enforcer named Park Joon Gil, played by Park Sung Woong. He decides that the best way to find him is to stick with his former girlfriend, bar hostess Kim Hye Kyung, played by Jeon Do Yeon. And before he realizes it he develops feelings for her.

Kim Nam Gil, 34, has not appeared on the small screen since the 2013 melodrama "Shark" with Son Ye Jin. He recently filmed "The Hymn," also known as "Dorihwaga" with Suzy Bae, whom he described as hardworking. He is currently contemplating a role in the film "Asura."

When asked if he would ever act with Jeon Do Yeon again, he said, of course.

"Next time I want to be fully ready to play alongside her at 160 kilometers (approximately 100 miles)."