Seo Ju-hyun, known professionally as Seohyun, is a South Korean singer, actress and songwriter. She debuted as a member of girl group Girls' Generation in August 2007, which went on to become one of the best-selling artists in South Korea and one of South Korea's most popular girl groups worldwide. Seohyun released her first extended play Don't Say No in 2017. She left SM Entertainment later that year, although she remains as a member of Girls' Generation. She joined Namoo Actors in 2019.

Girls' Generation-TTS is the first sub-unit of South Korean girl group Girls' Generation, formed by SM Entertainment in 2012. It is composed of three Girls' Generation members: Taeyeon, Tiffany, and Seohyun. The sub-group has released three extended plays: Twinkle, Holler, and Dear Santa.