'NCIS': Brian Dietzen on Co-Writing His First Episode and Possible 'Sydney' Crossover (Exclusive)

The actor previews Monday's dramatic episode and why he'd be game for a crossover with 'NCIS: Sydney.'

NCIS star Brian Dietzen is adding another credit to his name: writer. 

The longtime actor on CBS' popular procedural sat down with ET's Matt Cohen last week to discuss co-writing Monday's episode, "The Helpers," with writer/executive producer Scott Williams. In the episode, Jimmy and Kasie (Diona Reasonover) are exposed to a deadly biotoxin while investigating the death of an intruder at Quantico. For Dietzen, getting to help shape an episode of NCIS was the natural next step.

"I've been very, very fortunate to write a few different things. There were some feature films I co-wrote and some short films. I have always been interested in it and I have been doing NCIS, we are on our 19th season now, so obviously I have been enjoying the part of Jimmy Palmer for some time. And I think over the pandemic a lot of people started having to be quarantined and whatnot and asking themselves, 'What do I want to do?'" Dietzen shared with ET. "You see people switching their careers around a little bit or shifting their jobs and I am like, 'I don’t want to leave this job, I love it. But if I can do something more as well...'"

The actor said a discussion with showrunner Steven D. Binder opened up the "possibility" of him putting pen to paper for NCIS. After a quick greenlight from CBS, he and Williams got to work. "I couldn’t be more proud," Dietzen said of the experience.

He credited his castmates and the crew for making his first billed TV writing credit as seamless as possible. "With this family that we built over 19 years, everyone there is there to give you their best and say, 'Man, if you are going to write something, we are going to do it to the best of our ability and make it look good' and from everyone on our crew to our amazing cast to our writers, everyone did whatever they could to make this show the best it could be, so I was blown away."

Dietzen confessed it was a bit of an out-of-body experience hearing his words come to life at the first table read.

"This is something different because I have never had my co-stars -- I never had Wilmer Valderrama or Sean Murray say the words that I wrote before. So I am sitting there going, 'This is a different kind of pressure. I hope he likes this,'" he shared. "I am across the seat looking at him going, 'Did you...? Oh, he liked that one! OK cool!'"

"But the cool part about being on a show like this that is so long-term is that it is very familial. So my co-stars would literally come up to me and say, 'Hey, I think that this feels better this way.' Give me their input. 'And absolutely let’s do it that way,' and vice versa. While writing this with Scott, I would go down to the set and say, 'Hey, Katrina, I am thinking about this for your character. What do you think in this episode?' And she would give me her input and 'Cool, I am going to use that line,' and then go upstairs and throw it in. It was really collaborative, it was wonderful."

Speaking more specifically to the episode itself, Dietzen said he "wanted to write something that was putting the entire team in the crosshairs, so to speak." And they most definitely are as Jimmy and Kasie find themselves racing against the clock when they're exposed to a potentially fatal toxin down in her lab. As their team members try to find the antidote to save their lives, it's also the moment audiences meet Jimmy's daughter for the first time. 

"It's a huge day for our guy, Jimmy Palmer, and it's also a huge day for the relationship of Jimmy and Kasie. And it's a huge day for the NCIS team to save their family," he acknowledged.

Reacting to the recent announcement that the first international edition of NCISNCIS: Sydney, will be coming to Paramount+, Dietzen admitted he's never stepped foot in Australia and left the door open for a potential appearance if his number was called. But there is NCIS crossover on the horizon that he was more than happy to tease.

"We're doing our first crossover event with NCIS: Hawaii, which is gonna be in March, which is gonna be fantastic," he hinted. "A few of our characters went over there. We're also gonna see a couple of theirs, I think, mostly on screen. But the way that this universe can interact and coalesce, it's always been really, really cool. But I have a feeling that when NCIS: Sydney comes to light maybe a few of us might be going Down Under and checking out the sights and sounds of Australia. Hey, sign me up!"

NCIS airs Mondays at 8 p.m. ET/PT on CBS. 

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