Kim Woo Bin chose Park Shin Hye as the female co-star he was most comfortable with and Krystal as closest to his ideal type among the women of 'Heirs'.

On the January 7th broadcast of MBC FM4U's 'Park Kyung Lim's 2PM Date', Kim Woo Bin shared, "Among Park Shin Hye, Krystal, and Kim Ji Won, the actress I was most comfortable with was Park Shin Hye. I am comfortable with her like one of my guy friends. Not saying I saw her as a guy, but just that I was that comfortable with her."

He added, "Park Shin Hye is a very hard-working person and always has an overwhelming fighting spirit. She also takes care of the staff well. Rather than as a girl, I see her as a peer... Once the filming starts, she looked at Young Do as Eun Sang would. I also looked at Eun Sang in the same way."

DJ Park Kyung Lim then asked about the actresses, and Kim Woo Bin shared, "All of the girls made the male staff very happy on set. The entire staff especially liked Krystal. Whenever Krystal filmed, there were a lot of people on the sidelines. Whenever I filmed, many of them went to the bathroom."

"Among f(x), Krystal is closest to my ideal type. Because I am close with her. I've never seen the other members up close and I am not close with them."