There are, at least, three bands known as 2AM. 1) 2AM is a South Korean four-member ballad boy band under JYP Entertainment. The members are Jung Jinwoon , Jo Kwon, Im Seulong, and Lee Changmin. 2AM is one of the two subgroups branched out from the eleven-member (before Jaebeom's departure) boy band One Day, the other being 2PM. They officially debuted on July 11, 2008 on KBS's Music Bank, performing their debut song "This Song".
Secret (시크릿) is a girl group under TS Entertainment. They debuted in October 2009 in South Korea with the single I Want You Back, they rose to prominence in 2010 with the song Magic from their first mini album Secret Time (EP), which peaked at #4 on KBS Music Bank. ★ MEMBERS Jung HyoSung (전효성) ~ Leader
Jung HaNa (정하나) a.k.a Zinger (징거) ~ Rapper
Song JiEun (송지은) ~ Main vocal
Han SunHwa (한선화) ~ Maknae
TVXQ (often stylized TVXQ! or TVfXQ), an acronym for Tong Vfang Xien Qi (東方神起), is a South Korean quintet (by now continuing as a duo as of December 2010, due to three of the members filing lawsuit against SME) formed under SM Entertainment in 2003. In South Korea they are known as Dong Bang Shin Gi (동방신기, DBSK); they were later introduced in Japan as Tohoshinki (東方神起, Tōhōshinki) under the Avex sub-label Rhythm Zone in 2005. Their name translates as "The Rising Gods of the East".
MBLAQ, (an acronym for Music Boys Live in Absolute Quality) is a South Korean quintet boy band created by Korean pop R&B singer, producer and actor Rain (비) under a branch of his label J.Tune Entertainment called J.Tune Camp. The five members include Seung Ho, G.O, Joon, Thunder/Cheon Doong, and Mir. The group debuted on October 9, 2009 at Rain's Legend of Rainism concert. On October 14, 2009 the group released their debut single album, Just BLAQ, which topped various on-line and off-line music charts in South Korea.
4minute (Korean: 포미닛) is a girl group from Seoul, South Korea, founded by cube entertainment in 2009. The group consists of Ji Hyun (남지현), Ga Yoon (허가윤), Ji Yoon (전지윤), Hyuna (현아) and So Hyun (권소현). 4minute was announced in May 2009 along with two of the group's members Nam Jihyun and Kim Hyuna, former member of Wonder Girls. On June 11, 2009, the silhouette teaser video was released online along with their official website.