B1A4 is a 5-member South Korean boy group under WM Entertainment. The group consists of 진영 (Jinyoung), 산들 (Sandeul), 바로 (Baro), 신우 (CNU) and 공찬 (Gongchan). The group were first introduced to the public by a webtoon on April 11, 2011. Ten days later, they made their official debut with "O.K" from their first mini-album Let's Fly.