Marg Helgenberger is an American actress. She was born on 16 November 1958 in Fremont, Nebraska, USA.

She began her on-screen acting career on the American daytime soap, Ryan's Hope (1982-85) as Siobhan Ryan Novak. But she is perhaps best known for her role as Catherine Willows in CSI: Crime Scene Investigation (2000-13). Her other acting work includes:-

• China Beach (1988-91)

• Species / Species II (1995 / 1998)

• ER (1996)

• Erin Brockovich (2000)

• Intelligence (2014)

• Under the Dome (2015)

William Petersen is an American actor and producer. He was born on 21 February 1953 in Evanston, Illinois, USA.

He trained to become a Shakespearean actor, working with the Steppenwolf Theatre Company back in the 1970s. His best known role to date, is as Dr. Gilbert “Gil” Grissom in CSI: Crime Scene Investigation (2000-13). His other acting work includes:-

• To Live and Die in L.A. (1985)

• Manhunter (1986)

• Fear (1996)

• Without a Trace (2007)

• Manhattan (2015)

-YOU ARE VIEWING A SUPERB, SIGNED AND MOUNTED COLOUR PHOTOGRAPH OF MARG HELGENBERGER AND WILLIAM PETERSEN AS CATHERINE WILLOWS AND DR. GILBERT "GIL" GRISSOM IN CSI: CRIME SCENE INVESTIGATION-