Eye Wink de Korogashite

Iori Minase still can't forget about his favorite idol, Chika Izumi, even after she retires. One day, rumors start swirling about the new super hot freshman transfer student, Chikage Misumi, which Iori couldn't care less about... until he realizes that Chikage's actually the grown-up Chika Izumi in the flesh! The once cute and dainty girl idol is now a tall, handsome young man. Despite his new look, Iori's heart still goes a-flutter when he's around him...! Chikage, on the other hand, loathes the fact that Iori knows his secret, and decides to manipulate the upperclassman's adoration for him to his benefit.

(Source: Renta!)