As first reported by TVLine, “Once Upon a Time” is currently casting all three “Frozen” roles for episodes scheduled to air in the fall of 2014. Viewers got a peek of Elsa in the Season 3 finale, and it now seems that the ice queen will appear in 9 episodes of Season 4. Anna and Kristoff will appear in an undetermined, smaller number of episodes.
From early character descriptions, it sounds like the “Frozen” group will closely mirror their film counterparts, with their stories picking up where the movie left off. Elsa and Anna will still be close, while Kristoff is adjusting to life in the Arendelle castle for the first time.