Diona Reasonover On Writing Her First-Ever Episode Of NCIS - Exclusive Interview

As Forensic Specialist Kasie Hines, Diona Reasonover had some big shoes to fill when Pauley Perrette left "NCIS" after playing predecessor Abby Sciuto for the first 15 seasons. But Reasonover has settled in nicely, striking an entertaining balance between her character and co-stars like Brian Dietzen, who plays Dr. Jimmy Palmer, and Mark Harmon, who starred as Supervisory Special Agent Leroy Jethro Gibbs until midway through Season 19.

With Season 20 in full swing, Reasonover has stepped into an exciting new role on the hit series: writer. She co-wrote tonight's episode, which airs on CBS at 9:00 p.m. ET/PT and is titled "Turkey Trot." In it, the NCIS team delves into an attempted assassination at a Thanksgiving-themed road race, and Kasie goes to dinner with Special Agent Jessica Knight (Katrina Law) at her sister's place to help keep the peace between the two squabbling siblings.

During an exclusive interview with Looper, Reasonover discussed what went into making the episode, what it was like replacing Perrette, and where she hopes her character's storyline goes.

Let's talk "Turkey Trot," the first episode of "NCIS" you helped co-write.

This is my very first time. I begged them this year, "Please let me write something." They said, "All right."

Which character were you most excited to write scenes for?

Definitely Knight. I absolutely wanted to dive into that character because she's so fascinating. Every episode, we learn something new, and it's such a fun puzzle to put together. I'll tell you something funny — this originally was not supposed to be a Knight and Kasie episode. It was originally going to be a Knight and Jimmy episode. He was going to accompany Knight for the Thanksgiving dinner.

At the time that [co-writer] Scott Williams and I were conceiving the episode, there was another episode — the one where we saw Knight's ex-boyfriend come back — that was going to be a Knight and Jimmy episode. We weren't quite sure what that one was going to look like as the script was being written. We switched it to Knight and Kasie. I truly begged Scott. I was like, "Please, Kasie's been through so much. Don't make her do this."

Why did it switch from Jimmy to Kasie, exactly?

I went to Scott Williams and said, "I love your writing. Will you please co-write with me?" He said, "Yes." He, in his infinite wisdom, knew that if we put Knight with any other agent, the episode would be five minutes long. Knight would immediately disarm them, and any other agent would also help take this guy down. It was always going to be between Kasie and Jimmy, and Scott said, "I know why you want it to be Brian [Dietzen], because Brian's wonderful, but it'll be very fun to explore this sisterhood, both in terms of Knight's sisterhood with her [actual] sister and Knight's sisterhood with Kasie." That was pretty irresistible, so I was like, "All right, fine. I'll have one more hostage situation."

As if that's going to be your last.

I know! When is somebody going to write Kasie's spa day where she gets to relax and eat pizza?

Was it hard writing for yourself?

Yes, but it was less hard writing for myself than it was actually being on set and having to act my own words. I spent so many takes being amazed by hearing everybody make this [script] sound so cool that I was calling for lines sometimes because I was so busy listening to everybody else. I was like, "I've forgotten my lines." I completely forgot how to act because I was so busy. The watch scene, where it cuts to me and I'm crying — that's not acting. Those are real tears. I was truly moved by Katrina's performance. That was truly one of the hardest things I've ever done.

Do you hope to write another episode down the line?

As soon as they let me, as soon as they tell me it's a possibility, I'm out of the gate. I'm jonesing to go. My fingers ... I already have the Final Draft document opened. I'm ready to go whenever they let me do it again, if they do. I loved it.

Can I give a shout-out to our director too? His name is Lionel Coleman, and that was his first "NCIS" original episode he directed. He worked on ["NCIS: New Orleans" and] "Hawaii" before, though, and he was the missing puzzle piece that we needed. He was so protective of the moments of the actors, and he made such a good environment that we were able to thrive. He was so collaborative. Sometimes, you walk in with directors and they have these wild ideas, and you're like, "Okay, great, take it away." But Lionel really wanted to collaborate, and I'm so grateful that he was our director.

It's been a few years, but what was it like replacing Pauley Perrette?

I had to reframe that for myself as not replacing — because truly, how can you replace someone who has been vital to a show for 15 years? That's a pretty daunting task. I had to hope for the best and trust that the legacy that she left, and that so many people had built, was going to be preserved. And it was. I was really fortunate. I came in, and the fans were supportive, and the crew and the cast were supportive. Can I tell you what my first week was like?

Please do.

I had just gotten knee surgery right before my original audition. I missed my audition because it was scheduled for the day after my surgery. By the time I finally made it to set, my leg was still messed up, and I had no idea what the script was going to be. I didn't know if they were going to want me to jump over a car or something. Instead, everyone — including Pauley, Mark [Harmon], up and down the board — was so nice, so sweet, bringing me ice packs all the time. It was the most wonderful, supportive environment. I knew right away. I was like, "This is where I want to be."

It also helped that half the cast has already had something like that. Everybody was like, "You need a good follow-up doctor? I've got a good knee guy. How are your shoulders? I've got a good shoulder guy." I was like, "Okay, this is getting a little ridiculous."

Did Pauley leave you with any sage "NCIS" advice before she exited?

It's been five years, and I have to think about whether she had any particular line she told me. She was always absolutely lovely and supportive. I don't know that she gave me any particular words that I can remember right now, only because it's been five years, but we still talk. We still do stuff together. She asked me if I would do a little video for the fire department, and I did it. I'll have to ask her, "Hey, now five years in, do you have any advice for the second five years?"

This is the first full season without Mark Harmon, although he remains an executive producer. You guys had a great dynamic on screen. What do you miss most about working with him?

Mark is so funny. He's always super respectful when you're doing your takes, but he's also very funny. He has a very natural sense of humor that cracks you up. [He's] such a sweetheart. I always call him the quarterback of our show, which is not exactly original because he is literally a quarterback. But he is an amazing leader, and I do miss that. I miss it so much.

He's still there. He still comes. He came to tell me how much he loved the ["Turkey Trot"] script. I'd love to think that I am the sole reason he drove up. I don't know if that's true, but he definitely is still very present.

Maybe we'll see him on screen again someday?

That's what I'm hoping for.

I read somewhere you don't like the sight of blood, and I'm wondering how that works on a show like "NCIS."

You heard correctly. I'm so happy to be on the show, but our props department is sometimes a little too effective. Sometimes, we're filming at 7 o'clock in the morning, and some of those autopsy bodies get pretty gory for breakfast, as far as I'm concerned. I pop my contact lenses out. If it's a really gory body and I have to be right in front of it, I will take out my contact lenses so I can't see it so well. That's my cheat. I'll never have LASIK.

You have Second City and Upright Citizens Brigade in your background. Do you use any of those comedy or improv skills on the show?

One of my favorite exchanges was actually improvised. There's a casino episode, or an episode where we're talking about a casino, and Brian [Dietzen] improvised that he had never seen "Casino" because it was rated R, which was so funny. We had this little back-and-forth where I rolled my eyes at him, and it's one of my favorite Jimmy-Kasie moments. I love their little dynamic. I love that they're best friends and that she's sometimes completely irritated by how sweet and normal he is.

That's a good segue because my very next question is about Brian and how you guys are close on the show and in real life, it seems. Are there any funny behind-the-scenes stories with him that you can share?

I'm constantly bothering this man to do TikTok dances. I'm absolutely sure every time I'm like, "There's no way you can do this full dance." He's always like, "Let's do it." He is absolutely the cutest, sweetest, funniest person. He's my bud, and he's just as lovely in real life as he seems on TV. I'm going to bother him and make him start taking me golfing.

What is one thing fans might be surprised to learn about Kasie?

I wish I had a good answer for this. I don't know. I'm still learning so much about Kasie. Even getting to write little things for her, I'm always surprised. I was surprised when she was taking that martial arts class, because I, Diona, like to sit on the couch. I was like, "Does Kasie need to do quite so much jumping?" They're like, "Yes, she does."

You mentioned an opposite thing, but what's the biggest thing you have in common with her in real life?

We're both friends with Brian Dietzen! Kasie is a lot more direct than I am. Sometimes I'm shocked by her. You'll see in the [upcoming] crossover episode — I don't want to spoil it — but she has some pretty candid conversations with Sam Hanna [LL Cool J from "NCIS: Los Angeles"]. I'm constantly amazed by how much that girl is like, "I will tell you exactly how I feel right now, no matter who you are." I'm like, "Kasie, come on. If we're going to get invited to hang out at dinner, you've got to be cool."

She does get to go to that fun Thanksgiving dinner [on "Turkey Trot"].

That's right, and she made her famous mac and cheese. If anyone knows me in real life, you know that my mac and cheese is absolutely amazing. I indeed have a great mac and cheese recipe.

What would be your dream scenario on the show? Where do you hope to see your character go in terms of storyline?

At this point, she's been kidnapped three times, so I would not mind a Kasie spa day. I don't know if anybody wants to give her a chance to rest. No, but seriously ... I'm looking for a relationship with Kasie. That's not something that we've gotten a chance to do. We've hinted at her having some stuff off-screen, but I want to expand her personal life [and] figure out what she does outside of work that's not just, "I'm taking martial arts class because I'm afraid, and I want to feel stronger." I want to see the fun things that she does. I want to see her maybe have a little love. That would be great — a love life for Kasie.

The "Turkey Trot" episode of "NCIS" airs tonight, November 21, at 9:00 p.m. ET/PT on CBS.

This interview has been edited for clarity.