"I Need U" (stylized in all caps) is a song recorded by South Korean boy band BTS as the lead single from their third extended play, The Most Beautiful Moment in Life, Part 1 (2015). The single was released by Big Hit Entertainment on April 29, 2015 in South Korea. It was the first of BTS' career to garner them a win on a South Korean television music show. Two remix versions of the song were subsequently released on the band's first compilation album The Most Beautiful Moment in Life: Young Forever in 2016. By September 2016, the song had sold over 800,000 digital downloads domestically. In December 2019, its music video became BTS' 14th to surpass 200 million views. A Japanese version of the song was released digitally and in physical format on December 8, 2015 through Pony Canyon in Japan. The physical single was certified gold by the Recording Industry Association of Japan (RIAJ) that same month for selling over 100,000 copies. The digital single received silver certification in June 2021 for surpassing 30 million streams. In 2019, Billboard ranked "I Need U" as the 80th greatest K-pop song on its list of the 100 Greatest K-pop Songs of the 2010s. BBC named it one of the songs that truly defined the 2010s, referring to it as the starting point where BTS would become worldwide sensations. Composition "I Need U" is "an expressive dance track that soars with BTS’ emotive vocals as whistling synths, reverberating hi-hats, and R&B-inspired riffs build upon one another to create a sense of melodic despondency." The song serves as “the start of one’s young adulthood, in which beauty coexists with uncertainty, and focuses on the uncertain future more than the glamour of youth.” The original version of the song is in the key of F minor and 158 beats per minute. Background and release The Korean version of the song was not released as a separate single. In Japan, a physical release of the single was announced on November 12, 2015. On December 8, the single was released in Japan through Pony Canyon. The tracklist included two B-side songs that were also Japanese versions of songs from the original Korean EP. Four editions of the single were made available for purchase: a CD-only regular edition that included one of eight collectible photocards (first press albums only); a CD+DVD limited edition that contained album