The American actor debuts his British accent and a drastic bowl haircut as wayward Prince Hal who has turned his back on royal life and is living among the people.
When his father dies, he is crowned King Henry V and is forced to embrace the life he had previously shunned.
The short trailer sees Chalamet's young king navigating the palace politics, chaos and war his father left behind, and the emotional strings of his past life.
The star-studded film from director David Michôd also features Joel Edgerton, Sean Harris and Lily-Rose Depp, as well as Robert Pattinson as the Dauphin of France, and Ben Mendelsohn as Henry IV.
The King will be released on Netflix in the autumn.