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Changmin made his debut in 2003 as a member of the South Korean boy band TVXQ. Formed by SM Entertainment, TVXQ initially comprised five members: U-Know Yunho, Choikang Changmin, Kim Jae-joong, Park Yoo-chun, and Kim Jun-su. The group debuted on December 26, 2003, with their first single, "Hug."