Kim Ryeo-Wook (born June 21, 1987), best known mononymously as Ryeowook, is a Korean singer-songwriter and occasional actor. He is affestionately known to Elfs (EverLastingFriends, Super Junior's fan club) as the 'eternal maknae' because of his baby looks, despite being older than both Kyuhyun and Ki Bum in the group. He is one of the three lead vocalists of the super boy band Super Junior, and is also a member Super Junior-K.R.Y and Super Junior-M, two subgroups that are branched out from the main group. Along with four other members of Super Junior, he is one of the first Korean artists to appear on Chinese postage stamps.
Ryeowook was the last to join Super Junior before Kyuhyun, and did not join the group until several weeks before the group's official debut in 2005. His late addition was rumored to be a replacement of a previous SM trainee that was supposed to debut as a member of Super Junior 05, the first generation of Super Junior.
On November 6, 2005, Ryeowook along with eleven other members of Super Junior 05, officially debuted on SBS's Popular Songs performing the first single "TWINS (Knock Out)." The group released their full studio album a month later, and the album debuted as #3 on the monthly MIAK K-pop album charts. As the group's second single, "Miracle", came to an end, his talent agency was about to recruit new members for the next Super Junior generation, Super Junior 06, with Ryeowook staying as an undergraduate member. However, plans changed when the company added in a thirteenth member, Kyuhyun, and the company declared that future Super Junior generations were rumors. The group dropped the suffix "05" and became officially Super Junior. The new group hit big after they released their first CD single "U" the following summer in 2006, which became Super Junior's most successful single in the music charts, leading Super Junior to set #1 records in their music career since then. A year later in the fall of 2007, the group released their second official album, Don't Don, which became Super Junior's best-selling album and Korea's second best-selling album of the year.
In late 2006, Ryeowook became a member of Super Junior's first subgroup, Super Junior-K.R.Y. The trio debuted on November 5, 2006 on KBS's Music Bank. In early 2008, Ryeowook was placed in another Super Junior subgroup, Super Junior-M. The subgroup specializes in singing Mandarin songs, including Mandarin versions of Super Junior's Korean songs, bringing the K-pop influence into the Chinese music industry. Super Junior-M is the first international music group in the Chinese music industry to have members of both Chinese and Korean descent. The seven-member group debuted in China on April 8, 2008 at the 8th Annual Music Chart Awards with the release of their first single music video, "U". The subgroup released their first Chinese-language studio album, Me on May 2, 2008. The album debuted on Taiwan's G-music combo charts as #2 and #1 on many of China's and Thailand's music charts.