The project group also features a third member - producer Han Sang Won - participating as O.K's exclusive producer. The producer is well-known by fans as the mastermind behind SS501's 2008 hit "U R MAN", and for this project group's debut single, Han Sang Won has created a new track reminiscent to a part 2 of "U R MAN".
Titled "Why Are U Ok?", O.K's debut single will also feature another SS501 member, vocalist Heo Young Saeng. Fans can look forward to a unique concept combining the charms of K-Pop with a light air of Korean-comedy, when O.K's "Why Are U Ok?" drops on September 30 at 6 PM KST.