Kate Fleetwood is an English actress. She was nominated for a Tony Award for her performance as Lady Macbeth in Macbeth, at Chichester Festival Theatre and the West End and Broadway and an Olivier Award nomination in 2012 for her performance as Julie in London Road at the National Theatre. Her film and television credits include Vanity Fair (2004), Harry Potter and the Deathly Hallows – Part 1 (2010), Macbeth (2010), Philomena (2013), London Road (2015), Harlots (2017–2019), and The Wheel of Time (2021).

Lady Macbeth is a leading character in William Shakespeare's tragedy Macbeth. As the wife of the play's tragic hero, Macbeth, Lady Macbeth goads her husband into committing regicide, after which she becomes queen of Scotland. Some regard her as becoming more powerful than Macbeth when she does this, because she is able to manipulate him into doing what she wants. After Macbeth becomes a murderous tyrant, she is driven to madness by guilt over their crimes and kills herself offstage.