 By 2005 he had already begun starring in Korean dramas, such as sitcom "Orange" and "A Man and a Woman" in 2004.However Kim Jeong-hoon made his major break through when he starred in the hit MBC drama "Princess Hours" alongside Yoon Eun-hye and Ju Ji-hoon.Kim played the role of Yul, a caring and gentle 19-year-old who is second in line to become the crown prince and has returned to Korea to reclaim the two things that were snatched from him after his father's death