Alessandro Carloni and Erica Rivinoja say they love letting cast members improvise because it makes them look like better writers when actors come up with funnier stuff. Bill Hader performed extensive improvisation during voice recording sessions for The Cat in the Hat, portraying the title character while also playing the Cat impersonating others. He does a great Matt Berry impression and an impression of Alessandro that inspired the Italian chef character. The directors note some audio segments feature the Cat's voice played backward, created by Bill speaking in reverse rather than digital manipulation. They praise his significant control over vocal abilities, calling him a genius at doing different voices.