The live-actionproject, planned to begin pre-production in June, will star Colin Firth with other cast to be confirmed.
The production will be produced by Spice Factory, Forgan-Smith Entertainment and Csupo's own Grand Allure Entertainment.
Worldwide sales will be handled by UK-based Velvet Octopus on the film, developed with funding from the Australian Film Commission
The Moon Princess is planned as an 'FX heavy' fantasy in the Narnia mould, based on Goudge's book which has a huge US following and is said to be Harry Potter author JK Rowling's favourite story.
The script is written by Lucy Shuttleworth and Graham Alborough, and the film is planned to be 'FX heavy.'
Gabor Csupo has built a global reputation as a director and animator, co-founding the Klasky-Csupo animation studio that created The Rugrats and The Wild Thornberrys.
Michael Cowen of Velvet Octopus stated, 'Csupo wants to create a magical and engaging setting for The Moon Princess, Moonacre Valley, and has already rewritten the script with the authors to include many fantastical elements and inventive creatures.'
Bridge to Terabithia found an international audience, and Michael Cowen explained, 'The Little White Horse is a book that is famous with older generations.
Jason Piette, Managing Director of Spice Factory added: 'With Gabor at the helm we believe The Moon Princess has the potential to become a classic. He has a magical vision and an incredible sense of what makes kids tick. He will lend the film a richness and comic timing that is going to reach out and touch a wide audience.'