In late 2006, Ryeowook, along with fellow Super Junior members Kyuhyun and Yesung, formed a subgroup named Super Junior K.R.Y., a group specializing in R&B ballads. The trio debuted on 5 November 2006 on KBS' "Music Bank" with performing Hyena soundtrack called "The One I Love". Ryeowook made his acting debut in 2007, in the film, "Attack on the Pin-Up Boys", a high-school comedy/mystery film, in which he plays the eccentric vice president of the student council. He was nominated for Best Supporting Actor and Best Comedic Performance at the Korean Movie Awards.