Good news, Oncers! Frozen 2, the sequel to Disney's beloved film Frozen, is officially in development at Walt Disney Animation Studios. In honor of this cool announcement, here's a look at back at some of Anna and Elsa's shining moments  on Once Upon a Time of. The bond between these two very different women is sincere, sweet, and strong — in a word, a sisterhood.

1) Anna Tries on Her Wedding Gown
In "A Tale of Two Sisters," Elsa and Anna share a sweet sisterhood moment while preparing for Anna's wedding to Kristoff. 

2) Anna Comforts a Devastated Elsa
Elsa learns her parents were trying to get rid of her powers, and Anna is right there to comfort her.

Elsa Discovers the Truth About Her Parents|Elsa finds a disturbing truth in her mother's diary.|Anna comforts Elsa, who is distraught by a revelation in her mother's diary. From the Once Upon a Time season 4 episode, "A Tale of Two Sisters."

3) Anna Postpones Her Wedding
Anna is determined to find answers for Elsa — even if that means sailing away the day before her wedding to Kristoff!

Anna Turns to Grandpabbie Troll for Help|Anna asks Grandpabbie about where her parents really went.|Determined to find out the truth about her parents for Elsa's sake, Anna turns to her future in-laws for help. From the Once Upon a Time season 4 episode, "A Tale of Two Sisters."

4) Elsa Vows to Find Anna
When Anna sets sail for Mist Haven, Elsa vows to find her sister. 

Anna Sails to the Enchanted Forest|Anna goes on a mission to find the truth about her parents.|Elsa worries when Kristoff tells her that Anna has gone to the Enchanted Forest to find the truth about their parents. From the Once Upon a Time season 4 episode, "A Tale of Two Sisters."

5) Elsa Believes Anna
In "Smash the Mirror," the Snow Queen tries to convince Elsa that she can't trust Anna. But Elsa has faith that her sister would never betray her. 

Elsa Confronts Anna|Will Elsa believe Anna -- or the Snow Queen's lies?|Will Elsa believe Anna -- or the Snow Queen's lies? From the Once Upon a Time season 4 episode, "Smash the Mirror."

6) Elsa and Anna Finally Reunite
After being seperated by time and realms, the Arendelle sister are finally reunited in "Fall." Grab a hanky before you watch their emotional reunion. 

Elsa and Anna Reunite!|After nearly drowning with Kristoff, Anna is reunited with her sister.|After nearly drowning with Kristoff, Anna is reunited with her sister. From Once Upon a Time season 4 episode 9, "Fall."

7) Anna Reveals Why She Postponed Her Wedding
Moments before Anna's wedding the Kristoff, Elsa asks her sister why she postponed the big day to find out the truth for Elsa. Anna's answer sums up sisterhood perfectly. From the Once Upon a Time Season 4 Winter Finale, "Heroes and Villains."

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