The creator of Brave is furious at Disney bosses for giving the film's lead character Merida a more sexualised look in a new toy line.
Merida was a headstrong red-headed princess with unkempt hair and a normal figure in the 2012 animated film.
Pixar Animation Studios have narrowed the character's hips, altered her hair and redesigned her dress in a design for an upcoming toy.
Brenda Chapman, who created Merida before leaving Brave in 2010 over creative differences, criticised the makeover in a piece written for her local newspaper, the Marin Independent Journal
"I think it's atrocious what they have done to Merida. When little girls say they like it because it's more sparkly, that's all fine and good but, subconsciously, they are soaking in the sexy 'come-hither' look and the skinny aspect of the new version. It's horrible!
"Merida was created to break that mould," she said. "To give young girls a better, stronger role model, a more attainable role model, something of substance, not just a pretty face that waits around for romance."
A petition has been launched on change.org opposing the glammed up version of Merida.
"The redesign of Merida in advance of her official induction to the Disney Princess collection does a tremendous disservice to the millions of children for whom Merida is an empowering role model who speaks to girls' capacity to be change agents in the world rather than just trophies to be admired," it says.
Walt Disney Pictures, which owns Pixar, issued a statement defending the makeover.
It said: "Merida exemplifies what it means to be a Disney Princess through being brave, passionate and confident and she remains the same strong and determined Merida from the movie whose inner qualities have inspired moms and daughters around the world."