NCIS recently wrapped its 23rd season on the 2026 TV schedule, and both Sean Murray and Brian Dietzen remain the only stars who have been along for the ride since the very first season. While neither actor started on the show as a series regular, their respective characters Timothy McGee and Dr. Jimmy Palmer have become a vital part of the NCIS ecosystem. For his part, Dietzen will always give props to the late David McCallum for landing him the role of a lifetime.
In the latest episode of the NCIS: Partners & Probies podcast, which Dietzen hosts with co-star Diona Reasonover, the two spoke to Young Ducky actor Adam Campbell and took some time to remember McCallum, who passed away in 2023 at 90 years old. The late actor's Donald “Ducky” Mallard didn't appear as much in the later seasons, with the character becoming a mentor to Dietzen’s Jimmy, and their relationship off-screen was very much similar. Below, Dietzen credits McCallum for getting him a permanent spot on the show:
