Once Upon a Time is a 2008 South Korean film, directed by Jeong Yong-ki and adapted from a screenplay by Cheon Seong-il. The film is a heist comedy film set in 1940s Korea, and stars Park Yong-woo and Lee Bo-young as a con artist and a jazz singer, respectively, who each plot to steal a valuable diamond from the Japanese authorities. Once Upon a Time was the first major investment by SK Telecom's film division, established late 2007, and was released in South Korea on January 30, 2008, under the company's CH Entertainment banner.

Lee Bo-young is a South Korean actress, model and beauty pageant titleholder. She is best known for starring in the television dramas My Daughter Seo-young (2012–2013), I Can Hear Your Voice (2013), Whisper (2017), Mother (2018), Mine (2021), and Agency (2023). Lee was Gallup Korea's Television Actor of the Year in 2013.