Hush(2001)

Hush

Although Gyu Hwa Lee might look like a guy, she has feelings like any other girl. In fact, she's currently in love with Korean pop idol Kang Un Ryu. As luck would have it, Kang Un ends up transferring to Gyu Hwa's high school. The only problem is he has to keep his identity a secret so he's cross-dressing as a girl!

Description from Condensation