Credit: Getty Images Photo: Nathan Fillion at the EW and SyFy party

You must remember this: a kiss is just a kiss…

Except when it's the first smooch between Castle and Beckett! Then it's HUGE! And who better to weigh in on the Castle couple's first real step toward romance than Nathan Fillion himself?

"It's always a 'will they or won't they? Will they or won't they?' situation, and we have an episode coming up where they finally kind of put their toe in it and do the, you know, lip-lock," Fillion tells Wetpaint.

The scene in question has already been shot for an upcoming January episode, and Fillion says that the kiss that fans have been dying for is crucial – but neither the actors nor the production team had time to overthink everything the canoodling would mean after nearly three seasons of sleuthing and sexual tension.

"There's certainly a storyline it fits into," says Fillion. "But we're not sitting there kind of brooding about it and planning it. We were running late on a location. We were running out of nighttime. The sun was about to come up. We had to hustle. Although we want to do a great show, we still have to deal with the logistics of putting on a television show. We were working long, long hours. It was three o'clock in the morning. We had to hustle!"

While the story surrounding the kiss is still top secret, Fillion says he's encountered his fair share of fans who've been passionately arguing over whether smoldering mystery writer Richard Castle and hot-in-heels homicide detective Kate Beckett should give into their slow-burning chemistry – and their opinions have had an effect on his performance.

"No one's been aggressive or crazy about it," he says, "but everybody has their own ideas. And I encountered two people and they were both of differing opinions. One was saying, 'I can't wait for them to get together!' And the other one was saying, 'If they get together, that show is over! Everyone will stop watching.' And I didn't have to say anything. The two of them just argued it out for me. They came up with some actually real poignant points that I said, 'I'm gonna use that later on.'"

And as for the quality of the kiss, Fillion remains diplomatic – a smart move, considering he had real-life girlfriend Kate Luyben at his side when Wetpaint asked.

"You know what? I've been very fortunate in my career, both in dating and at work, to be able to make out with a long list of lovely, beautiful girls."