 After announcing that "Secret" was to become a full album on her official website, a message from Hamasaki on her TeamAyu fanclub website stated that she was doing overtime in the studio in order to complete the album on time.Hamasaki stated that "Until that Day..." was originally intended to be an instrumental track composed by CMJK.She loved the sound of the guitar and the b-melody and thus asked him to compose it into a full-length track.