"Once Upon A Time" season 4 spoilers are up and "Frozen's" Queen Elsa will make a recurring appearance on the series. However, at this point, nobody knows as to how she's going to be incorporated into the story arc. Not even series lead Jennifer Morrison.

Jennifer Morrison, who plays Emma Swan, dished out some "Once Upon A Time" season 4 spoilers in an interview with E! Online, specifically on the "Frozen" story arc.

"It's really big deal that they were even approved to use 'Frozen' in the show," she said. "I have no idea what they are going do with it. I know it's going to be out of this world, looking at the way they move around with people like Peter Pan (or) Wicked Witch from the Wizard of Oz."

"I'm fascinated how they are going to integrate people from 'Frozen,'" she added.

She said that she's blown away by what the writers of the show has done, allowing the characters to change and evolve, continue to make mistakes and learn from them.

Any favorite fairy tale she wants to join the show?

Jennifer Morrison said: "I'm literally running out of things to request because I feel that we added so many characters that I love, so many stories I grew up watching and loving.

Meanwhile, one character of the show that hasn't had a happy ending yet is Queen Regina (Lana Parilla) who constantly shifts from evil queen to good friend but in season 3, Emma snuffed her fairytale ending when Maid Marion was resurrected to be with Robin Hood, said Buddy TV's Gina Vaynshteyn.

Lana Parilla told E! that she's excited about the story arc the writers have prepared for her in season 4.

"I love that I've been able to pay all emotions, younger versions of her, older versions of her, future, past, that's what's keep it interesting for me is where she's been able to go and her growth as a person," she said.