Cheon Soo-yeon, born Cheon Seong-im on August 15, 1981, and known professionally as Song Ji-hyo, is a celebrated South Korean actress and model who has captivated audiences across Asia and beyond. She first gained recognition as a cover model for Kiki Magazine before transitioning into acting, but it is her decade-spanning role as a regular cast member on the variety show Running Man that has made her a household name and an international star.

Song Ji-hyo made her acting debut in the feature film Wishing Stairs in 2003, the third installment in the popular Whispering Corridors horror film series. This launched her into the world of Korean cinema, and she soon made her television debut in 2006 with notable roles in two major projects: the romantic comedy Princess Hours and the historical drama Jumong. These early works established her versatility and set the stage for a prolific career. Her filmography continued to build with critically acclaimed roles, including a powerful performance in the 2008 film A Frozen Flower and a standout turn in the 2013 crime drama New World, which solidified her reputation as a serious dramatic actress.

However, the defining moment of her career came in 2010 when she joined the cast of Running Man, a variety show that would become a global phenomenon. As one of the few female regulars, Song Ji-hyo earned the affectionate nickname "Ace" for her intelligence, athleticism, and competitive spirit, as well as "Monday Couple" for her on-screen chemistry with fellow cast member Gary. Her participation in Running Man brought her unprecedented international recognition, particularly in China and Southeast Asia, and she became one of the most recognizable faces in Korean entertainment. She has remained a core member of the show for over a decade, a testament to her enduring popularity.

In addition to her variety show fame, Song Ji-hyo has continued to build a strong acting career. She starred in the medical romance drama Emergency Couple in 2014, which was well-received by audiences. In 2020, she took on leading roles in two major projects: the romantic comedy series Was It Love? and the thriller film Intruder. Intruder was particularly notable as her first film released after the onset of the COVID-19 pandemic in South Korea, and it received a positive response from moviegoers, proving her enduring box office appeal even during challenging times. Through her combination of variety show charm and dramatic range, Song Ji-hyo has carved out a unique and lasting place in the Korean entertainment industry.