Kim Soo Hyun and Kim Ji Won first met in 2013, when they were both cast in the drama "Descendants of the Sun". They played the roles of Captain Yoo Shi Jin and Dr. Kang Mo Yeon, respectively. The drama was a huge success, and it helped to launch the careers of both actors.
In 2016, Kim Soo Hyun and Kim Ji Won reunited in the drama "Arthdal Chronicles". They played the roles of Eun Sum and Tan Ya, respectively. The drama was also a success, and it further solidified the popularity of both actors.
Since then, there have been many rumors about Kim Soo Hyun and Kim Ji Won dating. However, the two actors have never confirmed their relationship. They have always maintained that they are just close friends.