'Klaus' trivia and fun facts
Sami language
It was originally planned for the Sami people to speak English but this was later changed and they spoke only their native language in the movie.
Trip to Norway
Neda Labba, who voiced the Sami girl Márgu, did not speak any English. Sergio Pablos traveled all the way to Tromsø, Norway where she lives and did her whole recording session through translation and mimicry.
Rashida's second time
This is the second time Rashida Jones has voiced a character in an animated holiday movie. The first time was in 2018's "The Grinch", where she voiced Donna, the mother of Cindy Lou Who.
Memories from the past
During Klaus's flashback, both young Klaus and Lydia are shown to have dark brown hair. This strongly implies that the couple aren't natives of the island since the residents' hair color is either blonde (the Sami people), black (the Krums), or red (the Ellingboes).
A job change
Jesper was originally conceived as being a poor chimney sweep.
Inspired by 'Apocalypse Now'
Although Klaus is old school hand drawn animation the makers used computers to give the scenes a special, realistic light. The scene where Klaus is first seen coming out of the dark is inspired by the Colonel Kurtz shots from Apocalypse Now
In memory of Mary Lescher
This was the last film animator Mary Lescher worked on. The film is dedicated to her.
Jesper's origins
Jesper, is a Nordic transformation of Jasper, which is a German side form to Caspar. This name, in turn, is probably of Persian origin and means "treasurer". This foreshadows his role of helping Klaus deliver the toys ('treasures') to the children of Smeerensburg.
The esthetic of the film
When the animators were designing Smeerensburg, they used a lot of sharp angles and triangles to show that the environment wasn't friendly or comfortable. By contrast, Klaus's cabin and barn were made to look sturdy and strong, much like Klaus himself.
Santa's at the mall
JK Simmons, who voices Klaus, admitted that he once worked as a mall Santa as he was pursuing an acting career out of college.