Kim Yoon-seo, born Kim Ga-eun on January 15, 1986, is a South Korean actress known for her versatility in television and film roles. She made her official debut in 2009 but gained significant attention for her role in the acclaimed thriller film *I Saw the Devil* (2010). Her career has developed primarily in television, where she has played prominent roles in numerous series. Among her most notable works are the lead role in the daily drama *Glass Mask* (2012) and her acclaimed performance in *A Woman's Secret* (2016). She has also appeared in successful productions such as *A Gentleman's Dignity* (2012), *Graceful Friends* (2020), and *Doctor Lawyer* (2022). For her performance in *A Woman's Secret*, she won the Excellence Award, Actress in a Daily Drama at the 2016 KBS Drama Awards, an accolade that solidified her reputation as a talented actress in the Korean television landscape.