After releasing his album earlier this week, SS501's Kim Hyung Jun begun his promotions as a a solo artist on this week's Music Bank. By joining forces with Korea's hit producer, E-TRIBE, Kim Hyung Jun's urban R&B track, "oH! aH!," will certainly have fans exclaiming 'ooh!' over the exciting serenade of love. The song features the addictive 'hook' E-TRIBE is known for, mixed in with Kim Hyung Jun's distinctive vocal color, which all come together for a charismatic R&B track that will leave listeners captivated from start to finish. Check it out below!