Months after `` Once Upon a Time 's '' big season three finale reveal—Elsa has arrived ! `` Frozen '' is joining the fairy tale fray ! —the fantasy series has finally cast two key roles based on characters from Disney 's blockbuster musical . `` Greek '' alum Scott Michael Foster will play Kristoff , the rugged mountain man who befriends Queen Elsa 's younger sister Anna , played by newcomer Elizabeth Lail . EW has confirmed that both roles will be recurring in season four . Conspicuously missing is Queen E herself ; casting for Elsa has yet to be revealed . According to TVLine , which first reported the news , the `` Frozen '' arc will ostensibly pick up after the events of the film , with Anna and Kristoff already romantically linked and the latter adjusting to a new life as a castle-bound royal . See the original story at EW.com .
Elements from ` ` ' '' are not ` ` Once Upon a Time '' Casting for Elsa has n't been announced yet . The production will ostensibly pick up after the release of the film .