UPDATED: The ABC fairy-tale drama debuted a brief scene of Anna and Elsa in the season four premiere.

Once Upon a Time returned to Comic-Con, and the Ballroom 20 crowd was treated to special treats — including an exclusive Frozen first-look scene from the season four premiere.

The clip opens with Frozen's Anna (Elizabeth Lail) and Elsa (Georgina Haig) putting flowers on their parents' gravestones, with Elsa telling her sister, "Anna, they would be so proud of you." But that's not all, Elsa breaks the news that she has a surprise for Anna, but not just any surprise—it's for her wedding. The Frozen story line on Once will take place after the events of Disney's Oscar-winning film.

PHOTOS The Scene at Comic-Con 2014

The second clip, which was filmed just a few days ago, featured Regina (Lana Parrilla) going back to becoming Evil Queen, letting out her old friend, the Mirror (Giancarlo Esposito). Regina tells a bloodied Mirror, "There's somebody standing in the way of happiness. I need your help getting rid of them."

Much has been made about the ABC fairy-tale drama's move to introduce the major Frozen characters into the universe — including Kristoff (Scott Michael Foster) and Prince Hans — and the producers couldn't help but address it in a comedic way with a faux spoof of a writers' mini-camp and a cameo by executive producers Eddy Kitsis and Adam Horowitz's mentor Carlton Cuse.

New mother Ginnifer Goodwin, who couldn't make the session moderated by Community star Yvette Nicole Brown, filmed a funny video message on the Vancouver set, which included a cameo by Once Upon a Time in Wonderland star Michael Socha. Socha will reprise his role as the Knave in the mothership in the new season.

Below are some season-four teases, with the official teaser below.

Keeping Regina in check: After Emma unknowingly brought back Robin Hood's previously dead wife Marion back to Storybrooke, things are about to get rough for Regina. "It's an impossible situation. I can't apologize for saving a life and I'm horrified for getting in the way of Regina's happiness. It may spiral her back into her old ways," said Jennifer Morrison said of Emma's bind. "Emma's going to be determined to keep her in the good place in her life ... and keep something positive between them. It adds a nice element of conflict and concern." Added Parrilla, "She has something up her sleeve. Is anyone surprised by that? She's enjoyed being good; she's enjoyed discovering the light magic, but old habits die hard."

Hook in regular clothes: Looks like Captain Hook will finally get out of his period garb in the new season. "It'll be nice to wear something new," said Colin O'Donoghue, who revealed that Hook's jacket weighs 50 pounds.

Emma's true soulmate: Brown asked Morrison the impossible question of who she believed was Emma's true love, who punted the question to the producers. O'Donoghue played to the crowd, which was made up of a healthy number of Captain Swan fans, to drive some love for his character's burgeoning romance with Emma.

Josh Dallas on fatherhood: "Fatherhood is the greatest thing that's ever happened to me," he said of his newborn son with wife Goodwin. "Oliver is probably my soulmate for sure."

Once musical?: It won't happen any time soon. "The problem with doing a musical is we don't know how," Kitsis admitted. With several members of the cast having musical abilities, the possibility is always open. "We're willing to learn," Horowitz said.

Henry's new journey: Producers hinted that Henry will take up the family business — the pawn shop side of it — in the new season. Horowitz hinted that Henry's relationship with Mr. Gold will be further explored.

True love versus soulmate: Kitsis and Horowitz also clarified the difference between what a true love is versus what a soulmate is on the show. "True love is when you truly love somebody," Kitsis said. "Soulmate is the idea that there's only one person for you."

Belle and Rumple forecast: Rumple and Belle's wedding was genuine, Kitsis affirmed, even though Rumple's "weaknesses" may take over — especially following his dagger betrayal. How would Belle react if and when she discovers the truth? "I think she might be devastated," said Emilie De Ravin.

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