Fans have been eagerly awaiting Season 4 of "Once Upon A Time" after that surprising Season 3 finale that indicated "Frozen" was heading to Storybrooke. 

Adam Horowitz, the co-creator of ABC's hit fantasy series "Once Upon a Time", sent Twitter world abuzz when he posted a major teaser.

Casting for #OnceUponATime season 4! Hard at work! Hope to see ya this fall! pic.twitter.com/Zk5TWfAZnx

— Adam Horowitz (@AdamHorowitzLA) June 13, 2014

The series executive producer and writer posted a behind-the-scenes signage bearing the name of "Frozen" character Anna. The photo was accompanied by the caption: "Casting for #OnceUponATime Season 4!" Horowitz posted. "Hard at work! Hope to see ya this fall!"

It can be recalled that Elsa was clearly seen in the final scenes of "Once Upon A Time" Season 3. IB Times wrote, "In the final moments of the episode it was revealed that Hook and Emma accidentally brought a stowaway (besides Maid Marian) back from the Enchanted Forest of the past. An urn from Rumplestiltskin's dungeons poured out into the unsuspecting town, forming into the blue-clad ‘Frozen' Snow Queen, Elsa."

Given that the episode did show Elsa, could Horowitz's tweet be an indication that the sisters are both headed to Storybrooke?

TVLine reported that casting is underway for the famed snow queen. The website also wrote that Princess Anna and Kristoff will make an appearance in nine episodes of the series.

While no details on the plot and storyline have been provided, Horowitz did tell Entertainment Weekly that they don't plan on re-booting the film in the show because that's in no one's interest.

"But what we are going to do, we're not ready to tell you. But what we can say is we're very aware of what we think makes this character from ‘Frozen' so special and we want to honor that and make sure that what we do is in the universe of (what) everyone fell in love with this past year."

Sadly, the funny and lovable Olaf may not be making an appearance in the upcoming season. Prince Hans would have been another interesting character. In the meantime, the most important thing to note is how the "Frozen" characters can spice up the news season of "Once Upon A Time".

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