The hit ABC drama Castle has become one of the network’s most popular television series. Returning for its third season, things are definitely strained between mystery writer Richard Castle (Nathan Fillion) and his muse, NYPD Detective Kate Beckett (Stana Katic).

During Season 2, Castle and Beckett’s relationship grew stronger and, by the finale, the two were forced to confront their feelings for each other, but neither had the nerve to actually tell the other. So, when Castle left to finish writing his second Nikki Heat novel, Beckett was left wondering if he would ever return to the precinct. Castle is back for Season 3, but he will soon find out that not calling to let Beckett know is going to have him in a very unfortunate predicament.

In a recent interview, actor Nathan Fillion talked about shaking things up for Season 3, how being an actor is like living out his own personal fantasy and that he will always be grateful for the chance that Joss Whedon gave him to be a leading man. Check out what he had to say after the jump:

Question: What can you say about Season 3 of Castle?

Nathan: This year, we’re going to shake it up a little bit. There will be a little departure. We’re breaking the mold and we’re going to solve some murders. Then, we’re going to solve a couple more. The first season, Castle really blew it with Beckett, and then managed to mend some fences. In the second season, Beckett blew it. It was too little, too late. We now have two people who we know should be together and we want to be together, and they both know they want to be together, but now they’re with other people.

Since Michael Trucco has another series now, how will that work?

Nathan: We’re going to have to dance around that. That’s easy. We’ll get her another boyfriend. Piece of cake.

Do you think that, if the two leads get together, it will all be over? Is that the kiss of death of a series?

Nathan: We’ve all seen Moonlighting, but we’ve also seen Cheers. On Cheers, Sam and Diane were going to get married and, right at the last minute, she said no and blew it, and then he didn’t want her anymore and she had to convince him later. I think it’s a dance that people want to see. It’s a chemistry that people want to see. In the same way that people don’t want to see a perfect hero with no flaws who can handle anything, people don’t want to see a perfect relationship. There’s nothing interesting about that. People want to see you fail.

Do you feel like you’ve fully embraced this character now?

Nathan: Yes. When people embrace character, there’s latzie. It’s the stuffing of a scene that’s not written. It’s not in the stage direction and it’s not in the words. When people embrace character, it informs their living, breathing moments in a scene so well.

Did you get to spend much time with homicide detectives, when you were researching this show?

Nathan: When we were in New York City, we hung out with a bunch of NYPD homicide detectives. I think TV has been a little bit irresponsible in how they portray these people because homicide detectives are not brooding, tortured souls who are stained with the stink of the city and who have blood on their hands. They are real, live people that are incredibly entertaining. I heard some of the most amazingly funny stories from these homicide detectives. The only difference is that they started with, “So, this guy gets killed.” These guys, in particular, are so close to real life because they enjoy their jobs, they enjoy each other and they challenge each other.

What do you like most about your character?

Nathan: Castle is a guy living in a fantasy world. He’s in his imagination, writing these stories of murder. Now, he’s on the forefront of murder investigations with actual homicide detectives and he’s able to indulge this fantasy. He’s living it, in real life. Every day, for him, is a field trip. He’s so excited and happy. Castle isn’t really affected emotionally by murder. He’s thrilled about, “Oh, my god, I wonder how this happened?” Much in the same way that, since I was a kid, I wanted to be on TV and in the movies. When I saw a montage of Hollywood with the Hollywood sign and the palm trees, I said that it would be great to be there. And now, I’m living in Los Angeles, I’m in films and I’m on television, and I’m working with actors and telling stories. I’m living the fantasy. My worst day is a great day.

What is it like to be the face of a primetime television program?

Nathan: Certainly, there are challenges and stresses. Long hours will compound any stress you have. But, the fact is that I chose this career because I love it. I am one of the lucky few who is successful in their career, and I’m really enjoying myself. My worst day is still a really good day. I complain, but I catch myself and count my blessings. I am truly blessed. There are challenges and stresses, yes, but it’s not heavy lifting or rocket science. I think some people are built for it. Some people find it less or more challenging than others, but it’s a great job. I love my job.

When does Castle stop fighting?

Nathan: I don’t know that Castle knows he’s in a fight. He just keeps going. What I love about Castle is that he gets knocked down and he doesn’t know that he’s been knocked down. He thinks he’s pretty cool, and when things happen, to show everybody how cool he isn’t, he’s unfazed. It doesn’t bother him. I think that’s one of his strengths. He lacks a filter in what he does and says, on his actions going out. With the rest of the world coming in, he has a filter where he doesn’t understand that he’s losing.

The relationship between Castle and his daughter is really special. Was the chemistry between you and Molly Quinn there, from the beginning?

Nathan: As soon as she walked in the room. I sat in on so many auditions for Becketts, for Marthas and for Alexises, and all you want is for someone to walk in the door and be normal, accessible, real and just do an amazing job and knock it out of the park, and make you think, “Oh, my god, that’s the character.” And, that was Molly. She walked in, looked normal, was completely relaxed, looked you in the eye when she spoke to you, communicated, knocked it out of the park, took adjustments and knocked it out of the park again, stood up and said thank you, and then left. She left and they picked up the phone and said she had the job. That’s how she is, every day. She knows what she’s doing. She handles it incredibly well. She handles herself incredibly well.

Did you get to do any movies during hiatus?

Nathan: We did a 24-episode season last year and, if you watch the show, I’m pretty much in it, all the time. I had about two months off, and I took it off. I left town, I bought a house, I moved, I had family in town, and I packed and unpacked. I wasn’t able to get back to Canada, but I certainly did get out of town. I picked some tropical locations where you go, “Wow, this exists? Really?”

What’s it like for you when you go to conventions and you see so many people dressed up as your iconic characters?

Nathan: I completely understand because I’m a fan of Firefly. When I see people dressed up as that character, I get it. When I got to dress up as Malcolm Reynolds for Castle, I was thrilled. I got to spin the gun. On Firefly, I didn’t spin the gun. In Serenity, I didn’t spin the gun. On Castle, I got to spin the gun, so I got to indulge a little bit. When I see people dressed as Captain Hammer (from Dr. Horrible’s Sing-Along Blog), that was a blast. We did it in six days with friends. Everybody was a friend, and everybody was doing it free. It was a labor of love. There was one scene in particular where it was too dark to film the scene that we wanted to film and someone said, “I know what to do,” and held up a flashlight right in Neil Patrick Harris’ face, he started singing and that’s what we got. It’s a thrill to be a fan amongst fans. I can completely relate.

Firefly is an enduring hit, and Castle is a different type of hit. Do you have more enjoyment of one success over the other?

Nathan: It’s hard to shake a stick at success. The Castle success is obviously more apparent and mainstream. Just simply more people are watching the show. I did 14 episodes of Firefly. I’ve never done anything that has had legs like that show. People talk about it like it was yesterday, but it was eight years ago. That’s almost a decade ago. I went to Comic-Con and there was a 3-year-old boy dressed up like Malcolm Reynolds. That lights my fire. Kids are into it. People are still coming to it and enjoying it. That show and that experience has a very special place in my heart and in my life. That shaped everything.

That lead to a lot for you, didn’t it?

Nathan: Everything. No one has done more for me, in this town, single-handedly, than Joss Whedon has. He gave me my very first opportunity to step up and take a lead. No one wants to give you the opportunity. No one wants to give you the chance. No one wants to gamble. “Yes, he’s good, but we don’t know if he can handle a lead.” I heard that so much and it was frustrating. If you want a job, they look at your resume and say, “But, you haven’t worked.”

Are you hoping that Joss might find a role for you in The Avengers?

Nathan: That would be a lovely fantasy. The fact is that I’m on Castle right now, and that’s 10 months out of the year. So, unless they’re filming for two months, on my months off, there’s just no possible way it could logistically be done.

Do you still miss Malcolm Reynolds?

Nathan: I miss him terribly. I love that character. I loved how much he would lose. I loved that he was a loser. He kept losing, but it never stopped him. He would fight, knowing he would lose. I love that about him. He wouldn’t stop.

When you’re no longer acting, could you ever see yourself living the life of a novelist, like your character on Castle?

Nathan: No. I’m going to buy a houseboat and go somewhere tropical. It’s going to be one of those three-story houseboats and I’m going to live on the top two floors while the bottom floor is a general store for odds and ends.