Before Queen Elsa casts her icy spell on Once Upon a Time‘s upcoming fourth season, the powers that be need to do some casting of their own.

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Showrunners Adam Horowitz and Eddy Kitsis have confirmed to TVLine that Frozen‘s ice queen indeed arrived in Storybrooke at the end of Sunday’s finale, but her portrayer still remains a mystery, even to them.

Should it be another former Lost star, like Maggie Grace or Elizabeth Mitchell? Perhaps a teen drama vet, like Gossip Girl‘s Blake Lively or Glee‘s Dianna Agron?

Browse our gallery of potential Elsas below, then drop a comment with your own nomination(s).