Seo Ju-hyun (born June 28, 1991), known professionally as Seohyun, is a South Korean singer and actress. She debuted as a member of girl group Girls' Generation (and later its subgroup TTS) in August 2007, who went on to be one of the best-selling artists in South Korea and one of South Korea’s most popular girl groups worldwide. Apart from her group’s activities, she has established herself as an actress, notably through her participation in the original and Korean versions of stage musicals including Moon Embracing the Sun, Gone with the Wind and Mamma Mia. She released an extended play, titled Don’t Say No, on January 17, 2017.