On November 5, 2014, Ella Purnell was offered a role and was in final talks to join the film; it was also reported that Butterfield had been offered the male lead role, and was the favored choice.
5 Kasım 2014 tarihinde, Ella Purnell ile filmdeki bir rol için son görüşmelerde olduğu açıklandı; ayrıca Butterfield'a erkek baş karakter olarak yer alması teklif edildiği ve favori seçim olduğu bildirildi.