Stéphane Aubier Director Vincent Patar Director Benjamin Renner Director Forest Whitaker Ernest Voice Mackenzie Foy Celestine Voice Paul Giamatti Rat Judge Voice William H. Macy Head Dentist Voice Megan Mullally Lucienne Voice Nick Offerman George Voice Jeffrey Wright Grizzly Judge Voice Lauren Bacall The Grey One Voice Susan Blakeslee Voice Ashley Boettcher Voice Ashley Brooke Nina Voice Marsha Clark Big Rat Nurse Voice Bob Joles Voice Daniel Pennac Writer, Screenwriter Eric Beckman Producer David Jesteadt Producer Michael Sinterniklaas Producer Fabienne Alvarez-Giro Film Editing Vincent Courtois Original Music Zaza Production Design Ned Lott Casting