There are countless times where you're trying to channel somebody who's not there, but that's what you have to do. But Audrey Geisel, who has executive produced this film and Horton, and who works remarkably close with me, is a great source of information. (The Simpsons creator) Matt Groening once told me that one of the most important roles that he fulfills on The Simpsons is being the keeper of the integrity of the original vision.