Dr. John Hamish Watson is the deuteragonist of the BBC series Sherlock and Sherlock Holmes' best friend and assistant. He is a former British Army doctor. Before marrying Mary Morstan, he lived at 221B Baker Street with Sherlock, a flat they rented from Mrs Hudson. He lived with Mary, whom he worked with before developing a romantic relationship. He is portrayed by Martin Freeman, who also played Bilbo Baggins in the Hobbit trilogy.