

In its first week of release, "Yorokobi no Uta" debuted at number 1 with 300,396 copies sold knocking off L'Arc-en-Ciel's " Seventh Heaven" from the top spot. The song was also sung as part of a medley performance on Music Station on December 21, 2007. The song was a part of KAT-TUN's 2007 summer nationwide tour set list and can be found on "Tour 2007 cartoon KAT-TUN II You" DVD which was filmed during their last tour date at the Tokyo Dome. The group also performed "Your Side" during the latter guest appearance. Other subsequent performances on television include Music Station on June 8 and again on June 22. KAT-TUN as a whole went on to debut the song on their own variety show Cartoon KAT-TUN on June 6. Tatsuya Ueda and Yuichi Nakamaru first performed the song live when they were guests on Shounen Club on June 3, 2007. The song was also used as the theme song for Tanaka's romantic comedy series, Tokkyu Tanaka 3 Go, which aired on TBS.

Though Jin Akanishi appeared in the music video for "YOU", this song is the first official single to mark his homecoming after a six-month hiatus which he spent studying English in Los Angeles. Koki Tanaka penned his own rap verses whilst the track was arranged by Gin.K. Express, Kis-My-Ft, A.B.C, Johnny's Jr."Yorokobi no Uta" was written and composed by N.B.Comics and zero-rock.
Fumetsu no Scrum (不滅のスクラム Immortal Scrum).Love yourself ~Kimi ga Kirai na Kimi ga Suki~ (Love yourself ~君が嫌いな君が好き~ Love yourself ~I Hate You I Love You~).Bokura no Machi de (僕らの街で In Our City).Kusabi -kusabi- (楔-kusabi- Wedge -Wedge-).Break the Records -by you & for you- ().Taguchi Junnosuke (田口淳之介) (Founding member left Spring 2016).Tanaka Koki (田中聖) (Joined in 2001 dismissed in October 2013).Akanishi Jin (赤西仁) (Founding member left March 2010).Unknown (Founding member left in 2001).Kamenashi Kazuya (亀梨和也) (Founding member) Leader.Nakamaru Yuichi (中丸雄一) (Founding member).
