Lee Chang-sun (Hangul: 이창선; hanja: 李昌宣; born February 7, 1988), better known by his stage name Lee Joon (Hangul: 이준; hanja: 李準) is a South Korean idol singer, dancer, actor and model. He was a member of the Korean male group MBLAQ until the end of November, 2014 when his contract with J. Tune Camp officially ended; on December 16, 2014 it was announced that he had departed from the group and for the time being he would focus on filming his then current TV series, MBC's Mr. Back.