Despite being surrounded by beautiful women during his filming during "The Heirs", Kim Woo Bin shared that he only thought of his co-stars as colleagues.

On the January 7 broadcast of MBC FM4U's 2'O Clock Date, he was asked who among the female stars he was closest to, and he answered, "Among Park Shin Hye, Krystal and Kim Ji Won, I was most comfortable to act around Park Shin Hye. This is not to say that she is like a man, but she was very comfortable to be with."

"Park Shin Hye is always full of life and energy. She works hard and takes care of everyone around her, so instead of seeing her as a woman, she seems like a good colleague to me," he said. "However, as soon as the cameras start rolling, I would see her through Young Do's eyes and she would become Cha Eun Sang to me."

When asked who among his female co-stars he thought of as a woman, he said, "All of the male staff members were happy to see the actresses, but Krystal was the most popular out of them all. When she films a scene, many of the male staff stay to watch her, but when it's my turn to film, they all go to the washroom," he said with a laugh.

Kim Woo Bin also shared, "Out of all the actresses, Krystal is closest to my ideal type. I like her the most out of the f(x) members, but it's because I haven't had the chance to meet the rest of them."