Fly Me to Polaris

Fly Me to Polaris is a 1999 Hong Kong romantic fantasy film directed by Jingle Ma and starring Richie Jen and Cecilia Cheung.

Because he was thebillionth to die and depart to Polaris, Onion is granted a wish. He wishes to return to Earth. But theres a limit of five daysdays. Unfortunately the rules stipulate that he cannot tell anyone who he really is and that, at the same time, he will be not be recognized as Onion himself by his former friends.Upon returning to Earth, Onion tries to talk to Autumn, who is upset over his death. He tries to tell her who he really is but cant without breaking the rules, and finds her being wooed by Dr. Woo. He wastes a few days trying to tell her but finally gives up and makes the most of the time he has with her. ........

Source: Wikipedia