King & Prince is a six-member Japanese idol group under Johnny & Associates that debuted in 2018. The group was originally a Johnny's Jr. unit, Mr. King vs Mr. Prince that composed of 2 separate units: Mr. King and Prince. The units later performed as one group for TV Asahi's Roppongi Hills Natsu Matsuri Summer Station in June 2015. Their debut was announced at a press conference on January 17, 2018 along with the establishment of Johnny & Associates' new record label under Universal Music, Johnny's Universe, with King & Prince becoming the first artists to sign under the label.
Their debut single "Cinderella Girl" was released on May 23, 2018. It is used as the theme song for the drama Boys Over Flowers Season 2 which also features member Sho Hirano as the lead role Haruto Kaguragi. The single is described as an upbeat song that uses beautiful melody expression faithful feelings toward a woman; a truly sparkling and classic love song well suited for a debut single.
Later in October of the same year, the group released their second single titled "Memorial." The single was used as theme song for television drama Bukatsu, Suki Janakya Dame Desuka? starring members Kaito Takahashi, Yuta Jinguji, and Genki Iwahashi. The single was released on October 10, 2018.