After School is a South Korean girl group managed by Pledis Entertainment. The group had their public debut alongside label mate Son Dam Bi in 2008. The group eventually made a proper debut on 17 January 2009 with the first single, "Ah!". Later that year, Uee joined the group, and After School released a second single, "Diva". Their official fanclub is called "Play Girlz".
In the fall of 2009, Soyoung left the group, which led to the addition of two members - Raina and Nana. The group then released "Neo Ddaemunae" ("Because of You"), which became their first chart-topping single. In March 2010, After School released their 3rd Single called "BANG!" with the addition of 8th member, Lizzy.
Park Gahee, After School's leader, started her career in the entertainment industry as a professional dancer for artists under both SM Entertainment and YG Entertainment, most notably for BoA. Kahi was also part of a Korean American girl group called S.Blush, whose first digital single peaked at #2 at the Billboard Hot Dance Chart. Nana was a contestant in the 2009 Asia-Pacific Super Model Contest.
After School, as a group, made an unofficial first appearance on 29 December 2008 at the SBS Song Festival 'S', performing "Play Girlz" with Son Dam Bi. In the beginning on 2009, a few days before After School's debut, Pledis Entertainment officially announced that the group's music concept is heavily influenced by the Pussycat Dolls". On 15 January 2009, Pledis Entertainment released a 30-second teaser video on Gom TV, reaching 100 thousand views on the first day. Consequently, the group released their debut single, "AH!" alongside their EP, New Schoolgirl on 15 January'. On 17 January, After School made their live debut on MBC's, Music Core In April, the group announced a new member joining the group, Uee. Alongside the announcement, the group released the second single, "Diva" on 9 April 2009. The group made their comeback performance on April 9, 2009 on M!Countdown. On 21 May, the group released their third single, a cover of Morning Musume's "Love Machine", entitled "Dream Girl". In July, it was announced that the group would collaborate with popular artist, Son Dam Bi, for digital single, "Amoled", which was released on the 16th as part of promotions for Samsung's phone, Amoled.
On October 29, 2009, Yoo Soyoung officially withdrew from the group citing health problems as the cause of departure (This was apparently eventually dealt with, as Pledis Entertainment announced on May 3, 2010 that she will be making a comeback in August, though not with After School). She was then replaced by two new members, Raina and Nana. After School made their comeback on 25 November 2009 with their single, "Neo Ddaemunae" ("Because of You"), with teasers being released a day before. Marking a change for the group to a more mature and sophisticated concept, the song proved to be popular, winning three Mutizen awards and topping various online music charts. A remixed version was also released afterwards.
On March 17 2010, details surrounding a new member, Lizzy, were announced, following the release of the group's concept photos for the single album, Bang. Pledis Entertainment simultaneously announced that the album would be released on March 25, 2010.