Yoo Joon Sang revealed how he felt about idols starring in musicals.

As a famous musical actor and full-time musical professor, Yoo Joon Sang is known in the musical world. On the recent broadcast of 'Knee Drop Guru', he commented, "I worked on a lot of projects with idols. They're actually pretty good. As long as they do their best and keep their promises, I never punish them."

Yoo Joon Sang also revealed that he does not treat idol stars differently than professional musical actors revealing that no special privileges are granted to either group.

He shared his own way of discipline of making sure to enforce the importance of commitment and teamwork, stating, "In musicals, it's an absolute must that you arrive at the theater 3 hours before the curtains go up. I look at the clock and write down the people who don't come 3 hours earlier. As soon as they arrive, I dunk their faces in water. During winter, I make them rub their bodies with ice. The reason I do that is to let them know how important promises are, and I'm teaching them that they have to enjoy their work."