Bonnie Somerville (born February 26, 1974) is an American actress and singer. She has had roles in a number of movies and television series, most notably as Mona in Friends; she has also appeared in NYPD Blue, Grosse Pointe, The O.C., Cashmere Mafia, Without a Paddle, and Golden Boy. She starred as Dr. Christa Lorenson in season one of the CBS medical drama Code Black.