Fiona Shaw (born Fiona Mary Wilson; 10 July 1958) is an Irish film and theatre actress. She is known for her roles as Petunia Dursley in the Harry Potter film series (2001–2010), Marnie Stonebrook in the fourth season of the HBO series True Blood (2011), and Carolyn Martens in the BBC series Killing Eve (2018–22). For her performance in Killing Eve, Shaw won the 2019 BAFTA TV Award for Best Supporting Actress. For her performances in the second seasons of Killing Eve and Fleabag, she received Primetime Emmy Award nominations for Outstanding S…