Mulan, portrayed by Chinese actor Liu Yifei, is told that she must bring honour to her family by finding a husband.
The two-minute clip, unveiled on Thursday, revisits the story told in the 1998 animated film, which itself is based on the Chinese legend of Hua Mulan.
But as “Northern Invaders” (the Huns in the animated version) threaten the empire, each family is asked to send one man to battle them.
Mulan, convinced that her elderly father stands no chance on the battlefield, decides to pose as a young man to protect him and enlists in the army.