Duo U&U (デュオU&U) is the debut album by W, the duo formed by Morning Musume and Mini-Moni members and longtime friends Ai Kago and Nozomi Tsuji. Recorded while they were winding down their duties as Morning Musume and Minimoni members, the album consists of cover versions of songs released by other female Japanese pop duos from the later Shōwa period, including covers of songs by The Peanuts, Pink Lady, and Wink. The idea was that W were continuing the tradition that the original artists they covered on this album established, as well as give fans of Kago and Tsuji that had never heard the original recordings a taste of Japanese pop history.