who played gretel in once upon a time
âGretel to the Evil Queen. Gretel is a character on ABC's Once Upon a Time. She dÃ©buts, with her only appearance, in the ninth episode of the first season. She is portrayed by guest star Karley Scott Collins, and is the Enchanted Forest counterpart of Ava Zimmer. Gretel is based on the character of same name from the fairytale, Hansel and Gretel.