I had been speculating for some time on who may be cast in this film.  Deadline exclusively reports:

Timothee Chalamet is firming his first starring role since being Oscar nominated for his breakout turn in Call Me By Your Name. Chalamet will star as the title character in The King, a Plan B-produced drama helmed by David Michod. Production will start in June. Joel Edgerton and Michod wrote the script.

Chalamet will play the young Henry V. After his brother is killed in battle before his coronation, a young king is coronated in the late 1300s. The reluctant ruler wears the crown at a time when England was near a war with France, and the empire is teetering. He rises to the occasion, admirably. Plan B’s Brad Pitt, Dede Gardner andJeremy Kleiner will produce along with Edgerton and Michod. Liz Watts, who produced the Michod-directed Animal Kingdom and The Rover, are also producing.

Production is starting in June.  The article states in their byline that it’s Netflix, I thought it was Warner Bros – but I guess more information will come to light soon.  

Check out our The King film page for all updates.

UPDATED: 23 February 2018

Porchlight Films who are producing The King have updated news on their website as follows:

• Timothée Chalamet will play King Henry V in David Michôd’s upcoming film THE KING, from a script by Joel Edgerton and David Michôd.

  The King is an historical epic set against the varied textures of Medieval Britain in the early 1400s and based loosely on the life of Henry V, culminating in the famous English victory over French forces at the Battle of Agincourt. 

  … 

  THE KING will be distributed by Netflix.

IMDbPro has added Robert Pattinson to the cast and various media outlets are also stating that he will feature in this film, but that casting is yet to be officially confirmed.