The film's director and male lead, John Krasinski, played the creature in a motion capture suit for a few scenes.
Actress Millicent Simmonds has been deaf since infancy due to a medication overdose. This was the second film she starred in, with Wonderstruck (2017) being her first.
Emily Blunt did the bathtub scene in one take. According to John Krasinski, as soon as he said "Cut", Blunt left the character and asked the crew, "What's everyone having for lunch?"
The filmmakers purchased twenty tons of corn and hired local farmers to grow it.