Marg Helgenberger is an American actress best known for her role as Catherine Willows on the popular television series CSI: Crime Scene Investigation. Born on November 16, 1963, in Fremont, Nebraska, she began her career in the 1980s, appearing in various television shows and films. In addition to her work on CSI, Helgenberger has received critical acclaim for her performances in other projects, including the series China Beach, for which she won an Emmy Award. She has also appeared in films such as Erin Brockovich and Species, showcasing her versatility as an actress.