NCIS is an American police procedural television series, revolving around a fictional team of special agents from the Naval Criminal Investigative Service, which investigates crimes involving the U.S. Navy and Marine Corps. The series was created by Donald P. Bellisario and Don McGill as a backdoor pilot with the season eight episodes "Ice Queen" and "Meltdown" of JAG. The series premiered on September 23, 2003, featuring an ensemble cast, which has included: Mark Harmon, Sasha Alexander, Michael Weatherly, Pauley Perrette, David McCallum, Sean Murray, Cote de Pablo, Lauren Holly, Rocky Carroll, Brian Dietzen, Emily Wickersham, Wilmer Valderrama, Jennifer Esposito, Duane Henry, Maria Bello, Diona Reasonover, Katrina Law, and Gary Cole.