Red Velvet - IRENE & SEULGI (Hangul: 레드벨벳-아이린&슬기) is the first sub-unit of the five-member South Korean girl group Red Velvet, formed by SM Entertainment. It is composed of members IRENE (아이린) and SEULGI (슬기). The duo debuted on July 6, 2020 with Monster. It contains six tracks, including the title track "Monster." The duo's follow-up single "Naughty" was released digitally on July 20, 2020, and it was remixed by Demicat soon afterwards. Read more on Last.fm