The lyrical chanting heard at several pivotal points comes from the play itself. "Hamlet" Act 2 scene 2 page 5 when Ophelias father Polonius reads aloud a letter from Hamlet containing the lines "Doubt that the stars are fire Doubt that the sun doth move Doubt truth to be a liar But never doubt I love"
Nathaniel Parker, who plays King Hamlet in this film, played Laertes in Franco Zeffirelli's version of Hamlet with Mel Gibson
Naomi Watts, George MacKay, and Daisy Ridley have all co-starred with Tom Holland, Watts in The Impossible (2012), MacKay in How I Live Now (2013), and Ridley in the upcoming film Chaos Walking (2018).
Daisy Ridley says to Prince Hamlet, "There are two sides struggling within you; one is baser, one is better." Ridley also plays Rey, a main character in Star Wars VII, VIII and IX (2015, 2017 and 2019, respectively) that discovers her abilities and connection to the Force, and must struggle and decide her place between the good and dark sides of it.