Grumpy Cat's Worst Christmas Ever
The voice of Grumpy Cat is spoken by the actress Aubrey Plaza. She did not know about Grumpy Cat before working in the movie. To prepare, she learned all about Grumpy's behavior. The movie had already been made when Aubrey did the cat's voice part. Instead of using her script, she made up most of Grumpy's lines that ended up in the movie.