In a recent interview:
Q: Who's the one who influenced you a lot regarding acting?
Jae: Park Yoochun sunbae and Kim Junsu sunbae? (Laughs) Kidding, the one who really influence me a lot is Ji Sung Hyung. He gave me a lot of help during my first Korean drama. Every time I encounter new dramas, he'll tell me "When you have decided to take up new dramas, remember to show the script to me" and he'll check it out. In order to provide me good recommendations and advice, hyung put in a lot of effort.
P/s: Isn't it so nice? I'm glad Jae got to know many good friends during his filming.