'9-1-1: Lone Star's' Ronen Rubinstein on T.K. and Carlos' Blossoming Romance (Exclusive)

9-1-1: Lone Star
Jack Zeman/Fox

The actor talks to ET about playing Rob Lowe's gay son on the Fox series -- plus, watch an exclusive sneak peek from Monday's episode!

9-1-1: Lone Star isn't afraid to put its first responders through hell and back, and young firefighter, T.K. Strand (Ronen Rubinstein), who happens to be the son of the fire captain Owen Strand (Rob Lowe), is certainly no exception. 

Ever since Fox's emergency drama, a spinoff of 9-1-1, launched earlier this year, it's had its fair share of nutty, larger-than-life cases -- from an exploding bull semen factory (yup, you read that right) to a Bird Box-esque horror show to a devastating tornado that ripped half of Austin, Texas to shreds. On Monday's episode, titled "Friends Like These," the chaos continues when Firehouse 126 gets called into assist on a horrific farming accident goes horribly awry (read: a man run over by his own tractor) and a memorial service that may turn into another funeral. (Watch an exclusive sneak peek below.)

But not in true 9-1-1: Lone Star fashion, not everything is about the cases. After keeping his cancer a secret from the majority of the firehouse (including his son), Owen finally came clean to T.K. about his deteriorating health. Owen wasn't met with anger or resentment, but a determination and a resolve from his son that they were in this fight together -- a stark contrast from the troubled, drug-abusing T.K. viewers met at the start of the series. And, of course, there's the promising start of a potential new relationship between T.K. and Austin cop, Carlos (Rafael Silva), that started as an ill-advised but may blossom into something deeper. 

Ahead of Monday's new episode, ET spoke with Rubinstein about playing Lowe's on-screen gay son, T.K. and Carlos' relationship and what fans can look forward to in the second half of the season.

ET: You're playing Rob Lowe's son on 9-1-1: Lone Star. Was your connection immediate?

Ronen Rubinstein: It was almost completely immediate. I remember walking into the room and feeling extremely comfortable with him. And before we read any lines or talked about the work, we sat down on the couch and we started talking about our lives. Once we started doing the actual audition together, it was immediate. There was a lot of giggling. There was a lot of improvisation. There was a lot of really, really beautiful chemistry that you can't really teach; it either happens or it doesn't. I remember within five minutes we started doing push-ups together. We were talking about our workout routines and our diet. Apparently, right after the audition they all knew: "He's the kid." Rob signed off on me and the rest is history.

In those discussions that you had with Rob, what did you guys talk about? Did you bring personal stories or family things that you had gone through in your real life that you thought could be incorporated into the show?

One of Rob's sons, Johnny [John Owen Lowe], is a staff writer on the show. He is the writer on episode six, and he's been in the writing process throughout the entire thing. He pitches his ideas, little nuances that he knows would be authentic to a father-son relationship because Rob is his dad. I think that helped a lot in creating an authentic relationship with specific details that only a father-son would know. We're shooting episode nine right now and the father-son relationship has been a dream. It really has. The way that they're making... I can't say much, but where they're leading the relationship to is going to be something very special and beautiful. I can't wait for people to see it. It's going to be insane.

Watch ET's exclusive sneak peek from Monday's episode below.

Owen has finally come clean to T.K. about his cancer and T.K. took it incredibly well. How does their relationship evolve as a result of this?

The writers did a beautiful job in starting the show off with Owen taking care of T.K. and looking after him and his issues. And then, literally halfway through the season, they flipped it and now it's T.K.'s turn to look after his dad. They're switching roles. The thing for T.K. is, yeah he's going through a lot of his own stuff, his own issues and his own history... But I think once his dad, who is everything to him, presented him with the cold hard fact of "I have Cancer. I don't necessarily know if I'm going to make it. I don't know how bad it is," T.K. puts his own stuff to the side and makes it completely about his dad -- as any caring child would. I think his only choice is to look after his dad. Everything else comes second.

What does T.K. in a caretaker role look like?

It's definitely adds a massive amount of stress and anxiety and overall pressure, and he's been going through a lot for the past five episodes. From the moment we see him [in the first episode] he almost overdoses [over] heartbreak, has to leave his home. There's a lot going on in the kid's head. This is just another massive hit. I think he handles it pretty well from [episode] five on. I think he starts getting used to Austin. He starts getting used to his firehouse. He starts getting used to this possible love interest in Carlos. And I think he's definitely a bit more ready to handle it than a couple of episodes ago. He's going to find every last bit of energy and strength in himself to do this for Owen. Because, like I said, he really is the most important person in his life.

You mentioned Carlos. A big portion of T.K.'s story is his romance with Carlos. Fans are engaged with that pairing. Did that surprise you? Are you excited by that? 

That definitely has been the most talked about topic on the show and it's definitely the most asked question for me. But I'm still not getting used to it and I sort of like that. It started, literally, from our very first promo when you saw T.K. and Carlos kissing. It's a special moment for television and for this couple to be portrayed and represented on network television because this is usually a couple that you would see on cable or streaming. The fact that [executive producer] Ryan Murphy and the writers are willing to show this on primetime television, it's pretty epic. I am beyond honored to be part of it. And I think that's why people are grasping to it and are connecting to it because they've never seen anything like this on their television. 

It's just nice to be able to connect with a big part of the world that looks like Carlos and T.K. And I love that the writers made it a normal thing. It wasn't a coming out story. A lot of times you'd see a gay couple on television there's something really dramatic and usually sad involved with it. And this is just like, "Yeah, this is just normal. This is just how it is". It's as if it was a straight couple on television. It's been amazing to be a part of that and to tell this story and to connect with so many people. I talk to people every single day about this and they're just beyond grateful to see this and they're excited to see where it goes.

Jack Zeman/Fox

What do you personally enjoy about T.K. and Carlos' blossoming connection?

The beauty of T.K. and Carlos is, on paper it seems like such a perfect relationship, but you have to remember that T.K. is going through so much in his own life. And on top of that, T.K. and Carlos are first responders and it's one of the most stressful careers you can choose, to be a fireman and a cop. This is a relationship that's going to have to grow in time in order to bloom into something truly beautiful and we definitely have glimpses into that. They definitely are extremely fond of each other, but I think they're both in a very delicate time in their lives, especially T.K. I hope for the best for this relationship.

After the last episode, it seems like they're in a good place and they're possibly starting to go steady. Is your hope that they get serious down the line?  Do they reach that point by the end of the season?

My hope comes from a selfish point of view because I just love working with Rafael Silva. Te more scenes I could share with him, the happier I'll be. [The last episode] was the first time that they showed themselves to another member of the team. They not only welcomed Paul (Brian Michael Smith) into their community, but they also showed Paul that, "Hey, we're a thing." It'd be interesting to see, down the line, how much of themselves they reveal to the rest of the crew. And yeah, oh man, I hope it works out because Rafael has been amazing. All the scenes with him are... they're usually my favorite. So, yeah, I sure hope so.

9-1-1: Lone Star isn't afraid to go there with its cases. There was the gruesome tiara incident, the exploding bull semen, the tornado episode... Looking ahead, what are you most excited for fans to see?

I can only really talk on a personal level. I'm just excited for people to see the journey that T.K. goes through towards the end of the season. And, most importantly, the journey that T.K. goes through with his dad. I think the end of the season will end on a really interesting [note] and... I can't say much, but it's definitely going to be big for T.K. and Owen. I can't wait to see the journey that we've went through and the ups and downs that they've faced throughout 10 episodes. I have a feeling people will not be disappointed.

9-1-1: Lone Star airs Mondays at 8 p.m. ET/PT on Fox.

To stay up to date on breaking TV news, sign up for ET's daily newsletter.