Ahead of David McCallum’s death last September, his NCIS costar Brian Dietzen was able to say goodbye in a touching way.
In an exclusive conversation with PEOPLE ahead of the NCIS tribute episode to McCallum, airing Monday night, Dietzen, 46, reflects on the last conversation he had with the late actor a few days before his death.
“I’ll say that I got to speak to him on his birthday, which was wonderful,” he says. “That was on a Tuesday. He ended up passing away that weekend, so he was already in the hospital and obviously not doing very well.”
In September 2023, McCallum died “peacefully” of natural causes surrounded by friends at New York Presbyterian Hospital, CBS announced at the time.
After studying at the Royal Academy of Dramatic Arts and doing several years in repertory theater in the United Kingdom, the Scotland-born actor moved to America in 1961. He landed the role of Illya Kuryakin in The Man from U.N.C.L.E. opposite Robert Vaughn. He earned two Emmy and a Golden nomination for the role. After joining NCIS in 2003, McCallum became best known for playing Dr. Donald “Ducky” Mallard on the crime series.
NCIS will honor McCallum’s legacy with a special episode on Monday. Dietzen, who plays the protégé of his character Ducky, was tasked with co-writing the tribute with executive producer Scott Williams.
In addition to wanting to “do justice in honoring a TV legend,” Dietzen tells PEOPLE that he and Williams wanted to “honor his memory by telling a good story.”
“I think everyone in their own way was mourning this loss,” he continues. “And I think that Scott Williams and I both had to recognize that we didn’t want this show to fall into, well, this is just going to be forty-two minutes of us mourning and crying. There has to be a celebration about this.”