Fans of “Rookie Blue” won’t want to miss this week’s episode of “Hawaii Five-O”, featuring a special guest-starring appearance from Missy Peregrym.

The former Constable Andy McNally will be playing Bridget, sister of Five-0’s Danny Williams (Scott Caan), who arrives in Oahu for a business conference and reconnects with her big brother.

“She is on a work trip, she’s struggling back at home, and there’s a very brother-sister, fight-y dynamic because he calls me out on some stuff,” says Peregrym of Bridget’s relationship with her bro. “It’s one episode, but we packed in a lot of stuff into five scenes.”

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Fans of the show won’t be surprised to learn that Danny is an overly protective big brother, which irks Bridget no end. “It annoys me, and we get into a huge fight over it,” reveals Peregrym. “It’s a quick arc, but I really enjoyed every scene because we got through a lot in that episode.”

For someone coming off a five-year stint on a show, what’s it been like to jump into an established series as a guest star? “It was intimidating,” she admits. “Everybody has their rhythm, their routine, they know each other, and you’ve got to pop in [as a guest star]. Especially in this scenario, where I’m supposed to be a family member. You never know how the chemistry is going to be.”

Luckily, she shares, “it ended up being fantastic. I had a really good time on the show,” and she adds that working with Caan was a joy, “because he’s a pretty hilarious person. He has a fun energy about him… he really wanted it to work. Once somebody is open and willing to play the game that way, it’s so much easier, because he wanted to make sure [our relationship ] was believable.”

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Peregrym admits the original “Five-O” was before her time, but she says that the legacy of the iconic Jack Lord-starring cop show remains huge in Oahu. “I’m kind of blown away by how much of a thing it is in Hawaii,” she marvels. “They’ve got the original locations of where they filmed, it’s like a tourist thing to do.”

After all those years playing a cop, did it feel strange to appear in a cop show, but not play a cop? “A little bit,” she laughs. “There was nothing procedural about my character.”

In fact, she admits she’s trying to stay away from cop roles at the moment. “McNally was such a big deal and such a long time for me, I just feel like I’d be putting McNally in another series. I just wasn’t interested in doing that… it just seemed so wrong to do, so it was really interesting to be part of a procedural but in a relational way.”

You can catch Missy Peregrym in the Dec. 9 episode of “Hawaii Five-0”, airing at 10 p.m. ET/PT on Global; you can also watch full episodes online.