Sooyoung.

Choi Soo-young, known mononymously as Sooyoung, is a South Korean singer, actress, and songwriter. She was a member of the short-lived Korean-Japanese singing duo Route 0 during 2002 in Japan. After returning to South Korea in 2004, Choi eventually became a member of girl group Girls' Generation in 2007, which went on to become one of the best-selling artists in South Korea and one of South Korea's most widely known girl groups worldwide.