Sergio Pablos Pumpkin, Olaf Director, Voice, Screenwriter, Producer Jason Schwartzman Jesper Voice J.K. Simmons Klaus Voice Rashida Jones Alva Voice Will Sasso Mr. Ellingboe Voice Norm Macdonald Mogens Voice Joan Cusack Mrs. Krum Voice Sky Alexis Ellington Girl 2 Voice Carlos Martínez López Co-Director Zach Lewis Screenwriter Jim Mahoney Screenwriter Jinko Gotoh Producer Matthew Teevan Producer Mercedes Gamero Producer Mikel Lejarza Producer Gustavo Ferrada Producer Pablo García Revert Film Editing Alfonso G. Aguilar Original Music