Louise Brealey is an English actress. She started her career acting in theater. In 2002, she made her television debut as Roxanne Bird in the BBC One medical drama series Casualty. After this, she starred as Judy Smallweed in the TV drama serial Bleak House, as well as played Harriet ‘Anorak’ Tate in Mayo. She also guest-starred in an episode of Hotel Babylon. In the 2010s, Brealey became further known for her role as Molly Hooper in the crime series Sherlock. She has also had performances in the films Containment, Back, A Discovery of Witches, The Widow, and Gomorrah.