Seohyun acts.
Seo Ju-hyun ( born June 28 , 1991 ) , known professionally as Seohyun , is a South Korean singer and actress . 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 also starred in the drama `` Moon Lovers : Scarlet Heart Ryeo '' . Seohyun ( born Seo Joo-hyun ) is a South Korean singer , member of Girls ' Generation and its subgroup Girls ' Generation-TTS .