Also Known As: In Guk Seo, Seo In-guk, 서인국, Seo In-gook, 徐仁国, Seo In Kook, 徐仁國
Biography: Seo In-guk (서인국) is a South Korean singer and actor. He launched his singing career after winning the talent reality show Superstar K in 2009, and made his acting breakthrough in tvN's Reply 1997.