S1, E6: Sang Hyun tells Mr. Choi that Hee Soo is not good enough to be a solo singer and asks him if he knows about Hee Soo dating Hyuk Ju. Mr. Choi calls them to his office, but Hyuk Ju brings Sang Mi and introduces her as his girlfriend. Hee Soo is surprised but keeps calm and says she would never date a backup dancer as her goal is to become a star. Hee Soo starts chasing Rex and ends up breaking up with Hyuk Ju. Soon, Hee Soo becomes a singer and Hyuk Ju swears he will never stand on stage again.