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.
Aside from her music career, she has established herself as an actress. Following her supporting role in the television drama Passionate Love and Moon Lovers: Scarlet Heart Ryeo, she starred in Bad Thief, Good Thief, Time, Private Lives, Jinxed at First and Song of the Bandits. Her film work includes Love and Leashes. She also participated in the original and Korean versions of stage musicals including Moon Embracing the Sun, Gone with the Wind and Mamma Mia.