Mark Harmon, who played NCIS fan-favorite Leroy Jethro Gibbs for 19 seasons, has been opening up about his time on the long-running CBS drama as he promotes his new book, Ghosts of Honolulu: A Japanese Spy, A Japanese American Spy Hunter, and the Untold Story of Pearl Harbor.

Speaking to ETOnline, Harmon, who left NCIS in 2022, revealed that he almost never did the show as he wasn’t looking to commit to a serialized drama at that point in his life.