The real mystery surrounding Castle star Nathan Fillion

NATHAN Fillion pulls no punches as he reveals what it’s really like working on a hit show. But what about the one question every fan wants answered?

HOW long will Nathan Fillion keep on playing mystery novelist Richard Castle?

That is the question Castle fans are asking as the US crime drama heads towards its sixth season finale.

Castle has already been renewed for a seventh season but it is anyone’s guess what the 43-year-old Canadian actor will do after that.

A year ago, news emerged that Fillion was a no-show on set, supposedly because he was locked in a dispute with his ABC bosses over his desire to move to a four-day work week.

In November, the National Enquirer revealed more trouble behind the scenes.

Fillion was reportedly upset that co-star Stana Katic, who plays NYPD detective Kate Beckett, was getting too much attention and screen time.

All of that comes after Fillion suggested in 2012 that seven seasons of Castle would be his ideal.

So is Fillion getting itchy feet? Is it time to move on?

“That’s a good question,” Fillion says between scenes on the set of Castle.

Fillion was reportedly upset at the amount of screentime Katic has received on the show. Picture: Supplied

“This is the longest time I’ve ever spent employed. This is uncommon — having a television show that is on the air and not in danger of being cancelled and successful for six wonderful years.

“This is a gift horse I do not look at in the mouth.

“(As an actor) I do get to do things that I’ve never done before — invest in character. I’ve never done a character for six years before. I feel like I know this guy (Richard Castle) pretty well, and I feel like the audience does too.

“The audience is invested (in the show and I don’t feel like they’re going to go anywhere any time soon. There is a wonderful security in that.

“(But) as an actor, yes there are fewer and fewer and challenges. So would it be nice to play another character once in a while? Absolutely.”

Making Castle isn’t glamorous, “it is a bit of a sacrifice”, says Fillion. Picture: Supplied / Bob D'Amico

The sheer number of hours on set seems to be an issue for Fillion. When you play the title character in a TV series, you are guaranteed to be in pretty much every scene.

There are plenty of days when Fillion doesn’t see the California sun. He arrives at the studio before 6am and doesn’t wrap filming until well into the night. No wonder he wants a four-day work week.

“This (Castle) is a machine — we have to make it work and the hours are incredibly long,” Fillion says. “It’s not a glamorous life. It is a bit of a sacrifice. You don’t have much real life. That is the challenge.

“In this environment we’re removed. We’re kind of locked in here. It is a walled compound in a big building with no windows. It seems a little insular. It seems a little confined at times.”

Katic pushed hard for her character Kate Beckett to become romantically involved with Fillion’s. Picture: Supplied /Bob D'Amico

Fillion can’t be unhappy with Castle’s ratings. The current series is the most successful yet with around 13 million viewers per episode in the US.

The popularity comes despite Fillion’s long standing objections to Castle and Beckett becoming a couple.

For years, Katic had been lobbying the show’s creator Andrew W Marlowe to allow Castle and Beckett to become romantically involved. Katic even reckoned they should have a baby together.

Fillion disagreed. He was adamant that it was the unresolved sexual tension between Castle and Beckett that kept audiences watching.

Fillion knew that shows such as The X-Files, House, and Moonlighting had slumped in the ratings once their lead characters became romantically involved.

Katic persisted and the rest is history. Castle proposed to Beckett at the end of season five. The current season started with Beckett accepting Castle’s marriage proposal.

Fillion’s dire prediction never eventuated.

Fillion kept it casual at Comic Con in San Diego last month. Picture: Getty

Marlowe has kept things fresh with a job dilemma for Beckett, a deadly toxin for Castle, and the reappearance of Castle’s mysterious father Jackson Hunt (James Brolin).

“I hate being wrong,” Fillion laughs. “My thought process was that it was wanting them to be together that kept people watching.

“I figured if you give them (viewers) what they want (Castle and Beckett a couple) it would let the air out of it and they would start changing channels.”

A recent episode where Castle and Beckett had to take care of a baby also showed that they have wildly differing views on children.

Marlowe promises the pair will walk down the aisle in season finale “For Better or Worse” but fans should expect a hitch. Castle is renowned for its cliffhangers.

“Andrew has done a lovely job,” Fillion says. “Once you have solved ‘will they or won’t they’ it doesn’t solve all their problems.

“There is just a whole new set. I think everything Castle and Beckett have come up against has been very reality-based — things that couples come up against in real life.”

ACTING A PASSION FOR FILLION

DON’T expect Nathan Fillion to find a new challenge on Castle by jumping into the director’s chair any time soon. Screenwriting is also off the cards.

Fillion suits up for the Guardians of the Galaxy premiere in LA. Picture: Getty

The 43-year-old star got his start in Theatresports with Rapid Fire Theatre before landing the role of Joey Buchanan on TV soap One Life to Live.

Fillion has also linked with producer Joss Whedon for TV series Buffy the Vampire Slayer and Firefly as well as movies Serenity and Much Ado About Nothing.

Acting is his passion.

“I love working a scene — the life between the lines,” Fillion says.

“You’ve got so much life on the page (script) but there is so much more to be had (in the acting).

“As far as how the cameras work and here’s the shots I need (directing), I don’t have that eye and nor do I have that burning desire to do it.

“I tried my hand at writing but I found it to be very stressful. I’m going to leave that to the smart people.”

■ Castle, Channel 7, Sunday, 10pm