In early 2005, Lee Soo-man announced that he had been preparing for an all-boy project group of twelve members to debut at the end of the year. He called this singing group to be "The Gateway to Stardom of Asia, as most of the members in this group were chosen for their experiences as actors, MCs, models, and radio hosts prior debut. Heechul and Kibum have already established actors at the time, and most of the other members had already made various kinds of appearances in television and media. Inspired by the rotational concept of Japan's girl group Morning Musume, Lee said that his new group would also experience line-up changes, with new members replacing selected members every year to keep the group constantly young and all-rounded. This concept was then newly introduced to the K-pop market.
] Super Junior 05 made their pre-debut performance on the Korean channel Mnet on September 11, 2005.