Koo Hye-Sun is a South Korean popular actress and also a singer, who has recently gained fame in the hit drama, Pure in Heart (열 아홉 순정) as a starring role, Gukhwa and also sang the title song of it. She is well-known for portraying Geum Jan Di in KBS 2TV's drama Boys Before Flowers together with Lee Min Ho, Kim Hyun Joong, Kim Bum and Kim Joon. Koo Hye-Sun also starred in many other roles.

She also has gained attention for appearing as a cameo role in the film, August Rush as one beggar. She is in YG Entertainment. She started debuting in drama by appearing in 2005's Nonstop 5.