Adam Campbell is crossing over to NCIS: Origins.

The NCIS vet, who has appeared on the mothership in flashbacks as a young Donald “Ducky” Mallard, will reprise his role in a Season 2 episode that will serve as a special tribute to the late David McCallum.

“We wanted to do this episode to honor the memory of our dear friend David McCallum,” NCIS: Origins co-showrunners Gina Lucita Monreal and David J. North said in a joint statement. “He was a beloved member of the NCIS family for so many years and we’re incredibly lucky to have the talented Adam Campbell back to bring the younger version of this iconic character to life once again. We even got to feature David’s music in the episode. We’re all very excited and can’t wait for the fans to see it!”

In the episode — which is named after McCallum’s 1966 release, “The Edge” — “Ducky is sent to Camp Pendleton to shadow the team while they work a case,” according to the official logline. “In the process, he reconnects with Gibbs after the two crossed paths years earlier.”

Campbell previously guest-starred in four episodes of NCIS as Young Ducky. His first appearance came in Season 12, Episode 3 (“So It Goes”), while his most recent encore came in Season 18, Episode 2 (“Everything Starts Somewhere”), which predated McCallum’s death by three years.

Campbell & Sean Harmon on NCIS CBS screenshot

This will mark Campbell’s first appearance opposite Austin Stowell. On NCIS, the role of Young Gibbs was inhabited by Mark Harmon’s son, Sean Harmon.