Yoo Ah In (Sungkyungkwan Scandal) was interviewed in KBS Entertainment Relay program last week. In their conversation, he talked about his first drama, a 2003 KBS Banolrim (according to drama-wiki) in which he starred with Go Ah-Ra. He was just 17yrs old then. Btw, looking at his filmography, all his drama were from KBS.
he looks like a 14yrs old boy!
He also showed his talent, he did the sketch himself.