Secret (시크릿) was a TS Entertainment 3-member girl group formed in South Korea in 2009. Members of the group were: 전효성 (Hyosung), 송지은 (Jieun) and 정하나 (Hana). The former member was 한선화 (Sunhwa), who left the group and TS Entertainment in October 2016. They disbanded in 2018. Secret was first introduced through a documentary program titled Secret Story which aired on the cable channel Mnet. The program chronicled their debut process and aired their invitation only debut show case which took place on September 29, 2009. The group released the MV for their debut digital single "I Want You Back" .