 He was a regular cast member from September 2013 until July 2014, making his stay in the program two months shy of a full year.In his last recording for the show, he mentioned that he felt pressured to talk about people close to him.On December 11, 2013, Super Junior released their fifth official Japanese single, "Blue World", which was the first song of the group involving Heechul after he came back from military service.