Seohyun ( born on June 28 , 1991 in Seoul as Seo Joo-Hyun ì ì # 1\/4 í ) is a South Korean K-pop singer and entertainer as a member of the girl group Girls ' Generation . Seohyun ( ; born on June 28 , 1991 in Seoul as Seo Joo-Hyun ì ì # 1\/4 í ) is a South Korean K-pop singer and entertainer as a member of the girl group Girls ' Generation .