After releasing his debut mini-album "Turn Me On" earlier today, SS501's Kim Kyu Jong followed up with behind-the-scenes photos from the set of his music video for "Yesterday". As he is the last of the SS501 members to finally make his solo debut, fans welcomed his return with open arms. Through "Yesterday", he completely sheds his idol image with a refined, mature look and a modern style. With the use of luxury cars and bright lights, the music video showed fans that Kim Kyu Jong could shine just as brightly on his own as with his group.  The unreleased cuts feature the star posing against his music video backdrop, looking deep in thought as he discusses a particular scene with his director. Check out the BTS cuts below! [gallery link="file" order="DESC"] Source + Photos: Sports Korea Tip: Jackwon