When he was in middle school, he and a few other friends formed the dance team A+, and they competed in various dance competitions around the country.
) or simply U-Know, is a South Korean singer, actor, and a member of the pop duo TVXQ. After over two years of training, Yunho debuted with TVXQ in December 2003.
Born and raised in Gwangju, South Korea, Yunho auditioned for the Korean talent agency S. TVXQ have released fifteen studio albums and performed on record-breaking concert tours; their sixth Japan-wide tour, the Time Tour, was the highest-grossing concert tour ever held by a foreign music act in Japan.
TVXQ are the first non-Japanese music act to hold a concert in the Nissan Stadium, Japan's largest outdoor stadium.
According to the Oricon, TVXQ records the most number-one singles for a foreign music act in Japan.
Around 2002, Yunho was selected to be a backup dancer for Shinhwa and was chosen to be part of the project boy band Four Seasons, which also consisted of fellow trainees Jaejoong, Heechul, and Kangin.
The project group was later dropped when Yunho and Jaejoong joined TVXQ in early 2003.
Seventeen-year-old Yunho was appointed as the group's leader.
He spent most of his high school vacations in Seoul training, only returning to Gwangju for the school years.
After losing his voice, Yunho considered giving up his training.
Throughout his years as a trainee, Yunho was put in four temporary groups, all which later disbanded.
In late 2001, at the age of fifteen, Yunho was featured as a rapper and backup dancer in Dana's debut single "Diamond", and briefly toured with her.