Kim Jae-joong (; born January 26, 1986), also known mononymously as Jaejoong, is a South Korean singer, songwriter, actor, director and designer. He is best known as a member of the Korean pop group JYJ, and was one of the original members of boy band TVXQ. Kim was also known by the stage names Hero Jaejoong (in South Korea), Jejung (ジェジュン) (in Japan), and 英雄在中 (영웅재중) (in China). Kim is now using Kim Jae-joong (JYJ) for his activities.

Kim Jae-joong (; born January 26, 1986), also known mononymously as Jaejoong, is a South Korean singer, songwriter, actor, director and designer. He is best known as a member of the Korean pop group JYJ, and was one of the original members of boy band TVXQ. Kim was also known by the stage names Hero Jaejoong (in South Korea), Jejung (ジェジュン) (in Japan), and 英雄在中 (영웅재중) (in China). Kim is now using Kim Jae-joong (JYJ) for his activities.