Kim Jae-joong, star of the series Triangle, is best know as a member of what pop group?
Triangle (2014 TV series): Triangle () is a 2014 South Korean television series, headlined by Kim Jae-joong who plays Jang Dong-chul, the second of three brothers. Kim Jae-joong:  He is best known as a member of the Korean pop group JYJ, and was one of the original members of boy band TVXQ.
JYJ