Olivia Kate Cooke (born 27 December 1993) is an English actress. She has appeared as Alicent Hightower in the fantasy drama television series House of the Dragon (2022–present), Emma Decody in the thriller Bates Motel (2013–2017), Becky Sharp in the period drama Vanity Fair (2018), spy Sidonie "Sid" Baker in the Apple TV thriller Slow Horses (2022), and Cherry Laine in the psychological thriller The Girlfriend (2025). In film, Cooke has starred in the horror film Ouija (2014), the comedy-drama film Me and Earl and the Dying Girl (2015), the thriller Thoroughbreds (2017), the science fiction film Ready Player One (2018), the comedy thriller Pixie (2020), and the drama Sound of Metal (2019).