If in Love... Like Them (2007)

Lee Na (Lee Hyo Ri) is a rising singer who was about to debut but tragedy struck her when she found out she had leukemia. Another girl took her place and sang her debut song at her concert. Now everybody thinks that the other girl is her. Jung Tae (Lee Dong Gun) survived a department store collapse only to find out that he has cancer. Lee Na and Jung Tae meet and fall in love.