Marg Helgenberger is an American actress best known for her role as Catherine Willows in the CBS police procedural drama series CSI: Crime Scene Investigation. She has also starred in other television shows such as China Beach, ER, and Under the Dome. Helgenberger has won numerous awards for her acting, including a Golden Globe Award and two Emmy Award nominations. She has also been nominated for a Screen Actors Guild Award and a Satellite Award.