 Toyosaki then performed the opening theme of the 2009 First Love Limited series , titled " Future Stream " with <unk> <unk> , Haruka Tomatsu , and Minako Kotobuki . Shortly after , the four formed the musical group Sphere . They are affiliated with Music Ray 'n , an artist management and publishing group of Sony Music Entertainment Japan . The theme was released as the group 's first single on April 22 , 2009 . 
