Katie Cassidy and Stephen Huszar on Being 'Smitten' While Filming Their Hallmark Christmas Movie (Exclusive)

They met as co-workers and left as a couple. The actors talk to ET about their fairy-tale romance while making 'Royal Christmas Crush.'

When Katie Cassidy signed up for her first Hallmark movie opposite Stephen Huszar, she didn't plan for it to turn into a real-life fairy-tale romance.

In A Royal Christmas Crush, the first of two "Christmas in July" movies this year, Cassidy plays an architect, Ava Jensen, who takes a job of a lifetime to work at the Royal Ice Hotel and unexpectedly crosses paths with Prince Henry (Huszar), quickly finding herself being swept off her feet in a whirlwind romance. As fate would have it, Cassidy and Huszar's onscreen chemistry turned into something more off-screen as well.

Cassidy confirmed in June that she and Huszar were officially dating, posting a sunny couple selfie on Instagram with the caption, "Welp, cats out of the bag…"

But as Cassidy shared, things didn't turn romantic with Huszar until the second week of filming earlier this year after the pair went out for a meal. "I think we went for lunch or something, and I noticed his crystals. I love crystals. And we started bonding over spirituality and I started to get to know the real Stephen," the 36-year-old actress told ET over Zoom with Huszar by her side, as they promoted their upcoming Hallmark film. (Watch an exclusive scene from the movie above.)

"And I was very smitten," Cassidy admitted, later joking, "How could you not be with a sh*t-eating grin looking at this horrible-looking person and this jawline?"

"And it just happened," she added. "I don't know, it just happened. But I think we had the same moment when we both realized we actually had chemistry."

Huszar, 39, noted it was one scene from the movie where both of them felt their feelings evolve into something more. "It was actually exactly the same scene," he confirmed. "So that was good. Our intuitions were both firing at the same time."

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As for how their working relationship evolved into a real-life one, the couple credited their mutual respect for each other as being key.

"I'm very open. When we first met, he didn't know who I was. I didn't know who he was. It was all very genuine and real and we took each other at face value," Cassidy said. "This may sound a little cheesy, but when you know, you know. Or it's meant to be. It's the universe. And timing is everything."

Huszar agreed, adding, "It's just getting to know someone and seeing that, well, there is a lot of commonality there and there's a lot of respect there. In many ways, not just our art form but other things in our lives. So that made it very interesting and different."

"And it's still learning and fully accepting a person without judgment from just being there," Cassidy chimed in. "And we've realized we work really well together. We travel really well together. We have so much in common. It's nice to also be friends with someone first, but then have it evolve into this beautiful [relationship]."

In the movie, Cassidy's Ava is transported into a new world and royal culture, which immediately piques her interest, as she gets to know Prince Henry.

"I think there's a lot of curiosity on Ava's part. There's this person who she sees who's so sheltered and has everything taken care of for him," she said of Huszar's character in the film, "and she's just very real and down to earth. I think that is where they both lift one another up and make each other better people overall."

"I address the nation in the movie and Ava, Katie's character, helps me prepare for that speech," Huszar previewed. "So there's a bit of a turning point that you'll see in that scene as well." 

"I love the friendship that they build and then you do definitely see that moment where it turns and there's the spark of chemistry between the two of them where I go weak," Cassidy gushed. "Literally, he's talking and I go weak at the knees and I almost fell over and then caught myself in the scene. I was like, 'Well, it works for the character!'"

The cute pair seemed open to making A Royal Christmas Crush into a potential franchise and sweetly sparred when asked if they'd want to work together again in the future. "Oh, I'm not sure about that," Huszar joked, while Cassidy quipped: "I got to call my agent... No, of course!"

"I want to see what happens," Cassidy said of possible follow-up movies. "Where is the royal honeymoon, royal wedding and the royal baby with Ava and Prince Henry?"

But for now, they're leaving it up to the universe to decide. "I very much live in the world of, the universe works for you and everyone when you allow it to," she said. "And I believe that if we're supposed to [work together again], we absolutely will. I would love to work with him all the time."

"If our intentions are there and if it's meant to be, then absolutely," Huszar agreed.

"That would be the dream, right? To work with your significant other," Cassidy said.

A Royal Christmas Crush premieres Saturday, July 8 at 8 p.m. ET/PT on Hallmark Channel.