I promise

 is the sixth single by King & Prince. It and sold about 616,145 copies in 2021, placing at number 8 on the Oricon Annual Single Ranking.

Tracklist
Regular Edition=

CD
Limited Edition A=
 * 1) I promise
 * Lyricists: KOMU & Kusakawa Shun
 * Composers: GRP & Kusakawa Shun
 * Arranger: Ikuta Makoto
 * 1) Winter Love Story
 * Lyricist: AKIRA
 * Composers: AKIRA & Kubota Shingo
 * Arranger: Kubota Shingo
 * 1) Glad to see you
 * Lyricist: Kawata Soichiro
 * Composers: Kawata Soichiro & Sasaki Nozomu
 * Arrangers: Masami Kawabata & Yasumasa Sato

CD

 * 1) I promise
 * 2) Little Christmas
 * Lyricist, Composer & Arranger: Mori Daisuke

DVD
Limited Edition B=
 * "I promise" Music Video -Story ver.-
 * "I promise" Music Video Making -Story ver.-

CD

 * 1) I promise
 * 2) Happy Holy Night
 * Lyricist: Kokubo Yuki
 * Composer: Kuwata Satoshi
 * Arranger: CHOKKAKU & Iwata Masayuki

DVD

 * "I promise" Music Video -Dance ver.-
 * "I promise" Music Video Making -Dance ver.-

Featured Members

 * Hirano Sho
 * Nagase Ren
 * Takahashi Kaito
 * Kishi Yuta
 * Jinguji Yuta

Trivia

 * The single's release was announced during the "King & Prince Concert Tour 2020: L&" on October 9.
 * The songs included in the single are written with the theme of "winter".