SEE ALSO: Actor Song Jae Rim unexpectedly passes away at 39

In an interview with OSEN, 'Tunnel' director Kim Sung Hoon praised Bae Doo Na for her unparalleled professionalism and refreshing attitude, especially among Korean actresses whose main concern is to look pretty on-screen. 

Kim said, "[Bae Doo Na] is embarrassed talking about her bare face. She says she only wore very basic makeup. There is basic makeup that is used right at the beginning and end of the movie. The kind of the plain, everyday makeup that a mother would wear. Aside from those scenes, Bae Doo Na was truly bare faced the entire time. What kind of wife would arrive to her husband's accident site with a full face of makeup on? Bae Doo Na says she just did what would be realistic. She also said she doesn't like for makeup to hide her emotions. It's not CGI. She really did appear pallid and exhausted...I was always impressed [wither Bae Doo Na's performance]. I just felt sorry that I couldn't film her more so that she'd come out more pretty."