Yook Sungjae is a South Korean idol-singer, actor and entertainer. He debuted in March 2012 as the youngest member of the K-pop group, BTOB. He also forms ¼ of BTOB’s sub-unit group known as BTOB-Blue which debuted in September 2016. Yook’s 3X2=6 (2019–2020) project which culminated in the release of his debut EP YOOK O'Clock in March 2020, marked his debut as a soloist.