Song Jieun, popularly known as Jieun, sometimes Ji Eun or Ji-eun, is a South Korean idol singer and dancer. She is best known as a member of a popular South Korean girl group Secret as the main vocalist of the group. Aside from being a member of Secret, she began a foray of solo activities in South Korea with her debut single "Yesterday" and participating in various OSTs. In 2011, she released her second single, "Going Crazy" featuring Bang Yong Guk which went to become her first number one single in the Gaon Charts as a solo artist. She is currently signed to TS Entertainment.