Lee Gi-kwang (, Hanja: ; born on March 30, 1990) is a South Korean idol, singer, dancer and actor. He was a solo singer under Cube Entertainment, also known by his stage name as "Ace Junior" (AJ) when he debuted. He released his first Mini Album "First Episode A New Hero" which features the works of the famous composer Brave Brothers. He is the main dancer, lead vocalist and visual of Beast.