Earlier this month, Lee Kwang Soo surprised the staff members of "Running Man" by appearing on set without his trademark mustache, which instantly created confusion and chaos. Shocked at the sudden change in his appearance, his "Running Man" co-stars ran up to him and immediately began asking, "Who are you?" Shyly, he backed away and confessed, "I feel empty without my mustache. It feels awkward." It seems like his new look inspired a change in behavior, as his co-stars began regarding him with caution. While they always used to comfortably call him 'Kwang Soo-ya~', they switched to the more honorific form, and stiffly called him 'Kwang Soo-ssi' instead. So what caused the image transformation?  The reason lay in his new role for SBS's "City Hunter", for which he plays a doctor of engineering with a prodigal mind for computers. The actor commented, "I shaved my mustache to better fit my character. I feel so empty, and feel as if I've been reborn." His new image can be seen through the April 17th episode of "Running Man". Source: Sports Seoul via Nate