Williams takes on the role of Parker-Bowles, Charles's longtime love. In real life, Parker-Bowles is preparing to be crowned as Queen Consort, but in the 1990s, she was still embroiled in drama regarding her role in the dissolution of Charles and Diana's marriage. Williams, known for her performance in "An Education," also recently costarred in a play with "The Crown" alum Olivia Coleman in the play "Mosquitoes" in 2021, per Town & Country. She takes on the role from Emerald Fennell, and will also play Parker-Bowles in the show's sixth and final season.