Lee Chang-sun (; born February 7, 1988), better known by his stage name Lee Joon is a South Korean idol singer, dancer, actor and model. He was a member of the South 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. Since early 2015 he has been signed to Prain TPC (a Prain Global company), which manages other actors such as Ryu Seung Ryong, Park Ji Young, Park Yong Woo, Yang Ik Joon, Moon Jung Hee and others.