Mary Marg Helgenberger (born November 16, 1958) is an American actress. She began her career in the early 1980s and first gained attention for playing Siobhan Ryan on the daytime soap opera Ryan's Hope from 1982 to 1986.
She is best known for her roles as Catherine Willows in the CBS police procedural drama CSI: Crime Scene Investigation (2000–12, 2013) and the TV movie Immortality (2015), and as K.C. Koloski in the ABC drama China Beach (1988–91), for which she won the 1990 Emmy Award for Outstanding Supporting Actress in a Drama Series. She also appeared in the TV series Under the Dome and Intelligence, and in the films Species (1995), Species II (1998), Erin Brockovich (2000), and Mr. Brooks (2007).
United States
