Pre-debut

Before Big Bang's major debuted, each member had his own degree of success and popularity in the entertainment industry. Leader G-Dragon and lead vocalist Tae Yang have already been with YG Entertainment since they were both twelve years old, both known as GDYB back then (Tae Yang's real name is Young Bae).[4] Member T.O.P was well known as an underground hip-hop rapper while Seung-ri was first introduced to the entertainment industry through the show Let's Cokeplay Battle Shinhwa.[4]

After the lineups for the group was finally made, the television network M-net released an eleven episode documentary that showed the members in training before their debut as an official group. The first six episodes detailed each individual member's background and motivation for becoming a singer. The documentary portrayed the arduous process of training by showing their dancing and singing practice sessions. Beyond being just a behind-the-scenes reality show, the series also eliminated various candidates unfit for Big Bang. Two members, SO-1 and Seungri (Lee SeungHyun) were considered for elimination, but they were given second chances to showcase their abilities in singing, dancing, and performing. However, this eventually resulted in Yang Hyun Suk (the CEO of YG Entertainment) dropping SO-1 because he lacked stage presence and was "too shy".[4] On the other hand, Seungri was able to successfully impress Yang with his dancing and singing skills, thus making the group. This documentary made the group members even more known before their debut in the Korean entertainment industry as Big Bang.

Before deciding on an official name for the group, the members had suggested several names, such as "Apex", "Stump," and "Diamond" before deciding upon "Big Bang."[4] To celebrate the end of the trials and the official lineups, producer and founder of YG Entertainment Yang Hyun Suk gave each the member a custom pendant.[4] Big Bang made their official debut at the YG Family concert, held on August 19, 2006 at the Gymnastics Arena in Seoul Olympic Park

http://en.wikipedia.org/wiki/Big_Bang_(group)