The blockbuster world of Frozen makes its icy foray into Once Upon A Time this week and Elsa and Anna fans aren't the only ones rejoicing at the two worlds colliding.
Young and old cast members are Frozen film buffs, from 14-year-old Jared Gilmore (Henry), who credits his twin sister for him seeing the film multiple times, to Prince Charming himself, Josh Dallas.
"I'm a huge fan," Dallas says. "I loved the movie and I loved the idea that it's a love story about two sisters, and is about two strong women finding and helping each other. That's what Once Upon A Time is all about - strong women. So it's a natural story and characters to come into our world."
Frozen's snow queen was first seen emerging from Rumplestiltskin's vault in last season's finale and the rest of her posse, including engaged Anna and Kristoff, join the series in the first episode.
Dallas can't share exactly how Elsa and company will affect Charming's world but he teases that his character's life will change dramatically as season four progresses.
"We're only on episode two, but ... Charming has a friendship somewhere in his past that you don't think is a likely friendship, but it's one that's important to him and changes the entire course of his life. That's all I can say."
Jennifer Morrison adds Emma may finally find a female bestie in Elsa and fans of the Oscar-winning film - which has a sequel in the works - will get to see more of the world of Arendelle unveiled.
"You'll see a lot of the back-story of those girls," she says. "We're setting up a lot of their world you didn't see in the Frozen movie - the same way we've done with the other fairytales that have been on the show.
"Our characters interact with them and are doing things that reflect what they've been through. [In the first episode] we jump straight into seeing Frozen infiltrated into the world of Storybrooke and there are several parallels between their world and ours, which we go straight into."
As well as the Frozen crew, this season brings the arrival of the "Queens of Darkness" - Maleficent, 101 Dalmations' Cruella de Vil and The Little Mermaid's Ursula - who will leave a tornado of evil in their wake.
Ruthless pirate Black Beard, played by New Zealander Charles Mesure, also makes a comeback in an upcoming episode, in which he becomes fully immersed in Frozen happenings.
"Blackbeard gets to beat up the cast of Frozen," says Mesure, who has also been juggling US series Girlfriend's Guide to Divorce. "Lots of fun!"
Once creators/executive producers Eddie Kitsis and Adam Horowitz hope Mesure and fellow Kiwi Rose McIver (Tinker Bell) will continue to make appearances on the series.
McIver is now busy starring on TV2's iZombie, but hopes to return when scheduling allows.
"Rose is great and such a strong Tinker Bell, so we loved her," says Horowitz. "And Charles just brings that Black Beard swagger. He's fantastic.
"We'd love to keep having them back - and we want to do better in New Zealand!"
Once Upon A Time returns to TV2 on Wednesday, screening at 9.30pm.