 In March 2019, it was reported that Zoey Deutch and Olivia Cooke were frontrunners for the lead live-action role of Kayla, “who teams up with Tom to stop the pesky Jerry from ruining an important event for herself.” Additionally, Yara Shahidi, Kelly Marie Tran, Becky G and Isabela Moner were in consideration for the role.Later that month, it was reported that Peter Dinklage was being considered for the role of Terrance, Kayla's boss and the human antagonist of the film.In April, Chloë Grace Moretz was in final negotiations to star in the film.