Eiji Wentz (ウエンツ瑛士) is a Japanese singer and actor. Wentz and Teppei Koike (小池徹平) forms the singer-songwriter duo WaT. The duo released their debut single Boku no Kimochi (僕のキモチ) in 2005. Eiji Wentz (ウエンツ瑛士) is a Japanese singer and actor. Wentz and Teppei Koike (小池徹平) forms the singer-songwriter duo WaT. The duo released their debut single Boku no Kimochi (僕のキモチ) in 2005.