Ahead of the premiere on 19 September, Wilmer joined NCIS: Hawaii star Vanessa Lachey to discuss their first major crossover, and after being asked by Entertainment Tonight which team has the "most swag" Wilmer was quick to respond: "I would say NCIS, Mark Harmon, sexiest man alive."
WATCH: NCIS teases major crossover event
The premiere wil see the NCIS team call in the help of their counterparts in Hawaii after Special Agent Alden Parker (Gary Cole) was framed for the murder of his former partner at the FBI.
He went on the run with his ex-wife Vivian (guest star Teri Polo) to clear his name, but in the final moments of the last season, we saw that Vivian had texted an unknown number to say she "had him".
Vanessa's Special Agent Jane Tennant and Ernie Malick (Jason Antoon) will appear in the episode as they are in town for a meeting with Director Vance (Rocky Carroll), which will set the stage for the crossover that will conclude with NCIS: Hawaii's season opener.
As for whether fans will ever see Mark return to the show - fans saw his character LeRoy Jethro Gibbs leave midway through season 19 after two decades with the show - Mark recently revealed that the opportunity to tackle "fresh" and "challenging" material is what kept him returning to the drama every season, alluding to the possibility that he felt that after almost two decades on the show, he no longer felt that was the case.
Wilmer and Mark have a close bond
"The character is living in Alaska as far as I know," he said before adding that he was happy with how things were handled. "Plot-wise, this character has taken the path that it did. I thought it was honest and [I was] OK."
Following Mark's onscreen departure, showrunner Steve Binder released a statement that heavily suggested Gibbs could make a comeback in future seasons.
Mark headed up the show for 18 years as Special Agent Gibbs
It read: "As an executive producer and dear friend, Mark continues to be an integral part of the fabric of the show. Our north star has always been staying true to our characters, and that truth has always guided the stories we tell and where those characters go.
"So regarding the future of Gibbs, as long-time fans of the show may have noticed over the years… never count Leroy Jethro Gibbs out."