Although Lady Macbeth's nationality is never mentioned on Shakespeare's play, it's presumed that she is Scottish. For the film, Marion Cotillard kept her French accent. Producer Iain Canning explained that her casting added another layer to the film, "it has allowed us, at the center of this story, to place a character who has an otherness, there's a slight sense of separation now, in Lady Macbeth, that she exists in the community but somehow has a slightly different agenda to the other women in that community. It adds complexity to the Lady Macbeth role", he said. Scotland had many French Queen Consorts, which would be plausible for Lady Macbeth to be French.
Marion Cotillard always dreamed about playing the role of Lady Macbeth, but thought it would be on the stage and in French. She'd never even considered taking part in a Shakespearean English production and worked hard to learn the Shakespearian language to play Lady Macbeth, despite the language barrier.
Visibility was so poor at the Isle of Skye during filming in early February 2014, that Marion Cotillard had strayed into a bog and disappeared from view. It had taken two crew members to fish her out while the mud sucked at her feet.
Michael Fassbender was cast after working with See-Saw Films' producers Iain Canning and Emile Sherman in Shame (2011). With Fassbender on board, attention turned to a director who could complement the lead actor's style and add a new layer to this classic play. It was a screening of The Snowtown Murders (2011) by Justin Kurzel, which convinced the producers to send the script Kurzel's way. After Michael Fassbender saw Snowtown, he asked his agent to set up a meeting with Justin Kurzel one year before the idea of him directing Macbeth had even been mooted. Casting Marion Cotillard as Lady Macbeth was a mutual desire of Justin Kurzel and Michael Fassbender.
Michael Fassbender is the fourth actor of the X-Men franchise to play Macbeth and the only one who never played the character on stage before. His co-stars James McAvoy, Patrick Stewart and Ian McKellen have all played the role on stage and on screen. Fassbender is the second Magneto, following two Professor Xs.
Three witches are mentioned in the play, but there are four in this film: three adults and a little girl. Director Justin Kurzel liked 7-year-old Amber Rissmann so much that he created a fourth witch for her. To make her look like a witch, make-up artists created a scar on her chin and three on her forehead, as well as plaiting her hair. Amber shot her scenes over four weeks; she had her own trailer and a tutor on set. She had one line originally, but it was cut.
Marion Cotillard is the first French actress to play Lady Macbeth on film in a English-language adaptation and the second to play the character in a British production after Simone Signoret played her on stage in 1966, at the Royal Court Theatre. Signoret and Cotillard are the only French actresses to win a Best Actress Oscar.
The Weinstein Company and Fox Searchlight had a fierce bidding war over the rights to the film. The Weinstein Company ended up acquiring U.S. and Canadian distribution rights from StudioCanal in October 2013.
The filmmakers' intention was to portray Macbeth as a victim of post-traumatic stress disorder and a product of war. For Michael Fassbender, this was a revelation. They also decided that a more fragile Lady Macbeth, with the two of them grieving for their lost heir at the beginning of the film, would flesh out the characters in a more original way and make the insane quest for power displayed by both more plausible, understandable, and more deeply tragic for the audience. The apparitions from Shakespeare's play were augmented for the film by turning even more characters into phantoms in order to show a more modern take on psychological disturbance.
The trivia items below may give away important plot points.
The plot differs in several aspects from the original source material: According to Shakespeare's play, Banquo's ghost would sit in Macbeth's seat during the banquet (aside the table in the movie). The Birnam Wood would "come to Dunsinane Hill" in the form of tree limbs carried by the English soldiers to cloak their numbers (in the form of ash particles in the movie). Macbeth himself would be beheaded by MacDuff in the end (opposite to the movie). There would be only the three witches without the child and the infant. Moreover, the movie subplot of Macbeth's dead child would be completely omitted.
The ending of the film is slightly different from the play. Macbeth is simply left lying on the battlefield while Malcolm enters the castle to be crowned as the new king. In the original play Macduff decapitated Macbeth. Although this scene was omitted from the film the ending is strongly suggestive. The last flash images in the movie have young Fleance tampering with the swords as if trying to decide which one to pick. It can be inferred that it is Banquo's son who exacts the final act of revenge for his father by delivering the fatal blow.