One Day (South Korean band)

One Day was an eleven-member South Korean band. It was started by Korean musician Park Jin-young. After performing as one group, it was splintered into two separate bands called 2AM and 2PM respectively.

Formation
A documentary called Hot Blood Men captured the group's rigorous training program. In this documentary, former member Jay Park (Jaebeom) finished at the top spot and received the most fan votes. It also featured the elimination of three trainees from the group: Lee Swichi, Jeong Jinwoon, and Yoon Doo-joon who were all cut. Jinwoon replaced Im Daehun upon the latter's withdrawal. By the end of the training process, One Day had been reduced to an eleven-member group.

Split
The band was then split into a four-member ballad group 2AM and a seven-member hip-hop group 2PM.

2AM (투에이엠), became a four-member boy band and ballad group consisting of
 * Jo Kwon
 * Lee Changmin
 * Lim Seul-ong
 * Jeong Jin-woon.

2PM, became a seven-member hip hop band formed by JYP Entertainment, consisting of
 * Jun. K (formerly known as Junsu)
 * Nichkhun known as Nichkhun
 * Ok Taec-yeon known as Taecyeon
 * Jang Wooyoung known as Wooyoung
 * Lee Jun-ho known as Junho
 * Hwang Chan-sung known as Chansung
 * Park Jae-beom known as Jaebeom