Chung mo yim (2001)

Lost in the woods, the Emperor Qi (Anita Mui) stumbles across local chief Wu Yen, his predestined bride, only to accidentally free a promiscuous fox fairy who promptly falls in love with both of them, changing between man and woman to clumsily woo each, setting the scene for a constantly shifting triangle with the emperor torn between both the fox fairy and Wu Yen and the fox fairy after whichever one will agree to marry her/him first.