NCIS Video: Brian Dietzen Cheers ‘Wonderful’ Weatherly Cameo, Shares Hidden David McCallum Easter Eggs

Now that NCIS‘ Ducky tribute episode has aired, the CBS procedural is pulling the behind-the-scenes curtain back on the hour’s very special guest, Michael Weatherly.

On Tuesday morning, CBS dropped on Instagram a series of BTS images from Monday’s special episode, which bid a fond farewell to Dr. Donald “Ducky” Mallard and, in turn, his portrayer, late cast member David McCallum.

More from TVLine

• Jon Stewart Pitches an Israel-Palestine Conflict Solution - Watch Video

• Biden Downplays Concerns Over His Age, Argues Trump Is 'About as Old as I Am' in Late Night Interview (Watch)

• NCIS EPs Talk Surprise Cameo, Why It Wasn't Mark Harmon: 'We're Not Going to Bring Him Back for 2 Minutes'

And on Tuesday afternoon, TVLine was on-set (for the filming of the NCIS franchise’s 1,000th total episode), where we invited cast member Brian Dietzen (who co-wrote the Ducky tribute with EP Scott Williams) to break down the surprise cameo.

At episode’s end, Jess and the others gave Jimmy a moment alone in the lab. Moments later, Special Agent Anthony DiNozzo, played by series vet Weatherly, came strolling in. After gifting Jimmy with a black bowtie that he had picked up en route to the States, Tony did his best Dr. Mallard voice while vividly recounting a Ducky-like anecdote. Tony then assured Jimmy that when we die, it’s not just “stories we leave behind,” as had been said earlier — but also the people whose lives we touched.

In the video above, Dietzen talks about how “wonderful” it was to hear that “familiar voice” break up Jimmy’s solitude.

“DiNozzo wasn’t there just to honor the loss of Ducky; he was also showing up for his friend,” explains Dietzen.

Dietzen then goes on to tally at least three “Easter eggs” that were scattered throughout the episode, as nod’s to McCallum’s previous roles in TV’s The Man From U.N.C.L.E. and the film The Great Escape. Did you catch ’em all?

Peruse all of the BTS images — including one featuring NCIS: LA alum Daniela Ruah, who as we speak is directing the franchise’s 1,001st episode (Episode 7 of NCIS: Hawai’i Season 3) — via the Instagram post below.

Best of TVLine

• 'Missing' Shows, Found! The Latest on Hacks, The Orville, Snowpiercer and 20+ Others

• Summer TV Calendar: Your Guide to 85+ Season and Series Premieres

• Yellowjackets Mysteries: An Up-to-Date List of the Showtime Series' Biggest Questions (and Answers?)

Get more from TVLine.com: Follow us on Twitter, Facebook, Newsletter