Regular-Irregular is the first studio album by South Korean boy band NCT 127, the second sub-unit of the South Korean boy band NCT. Described as a multi-genre concept album with a total of eleven tracks, the album was released by SM Entertainment on October 12, 2018, and distributed by IRIVER. This marks NCT 127's first Korean major release after a year and four months since their previous EP, Cherry Bomb, released in June 2017. It is also their first release as a ten-member group after Jungwoo was added in September 2018. It is also the group's last release featuring member Winwin, as he would focus his promotions on WayV following the album's release.