IU is an easy-going person. People in the world of k-pop sometimes say that she doesn't look like a celebrity because she fits in well with any crowd. When I saw her at an interview and press conference, she was cheerful and lively, but at the same time polite and had an old head on young shoulders. As she’s suffered hard times when she was an unknown singer, she's very modest about her success.
In 2011, through a telephone interview, I asked her "Don't you want to look pretty in your drama?" because she played a fat and ugly high school girl in her first ever drama “Dream high.” Wearing special effect makeup, she tried to pretend to be unattractive. Have you ever seen a k-pop idol star who tries to do such a thing?
Her answer was as follows. "Yeah, I want to look pretty, but it can't be helped because I have to play my character well. I can bear this degree of hardship." She spoke very lightly, and I was sure that she will grow up as a competitive actress because no other young idol stars have such a mature sense of responsibility.
Source : KpopBehind