|Boy group BTOB's Lee Chang-sub. Yonhap|
By Lee Min-young
Boy group BTOB's Lee Chang-sub will start serving in the military on Jan. 14, according to his management agency Cube Entertainment.
He is the group's second member to enlist after Seo Eun-kwang started mandatory military service in August.
A month ahead of his departure for boot camp, Lee Chang-sub will make his solo debut. His first solo mini album "Mark" is set to be released on Dec. 11. The album will have five new songs all of which he helped write.
Lee debuted as six-member group BTOB's lead vocalist in 2012. He also formed a sub-unit "BTOB-Blue" with members Seo Eun-kwang, Lim Hyun-sik and Yook Sung-jae. The unit most recently released its digital single "When It Rains" in August.