The Transformers director angered fans yesterday with the revelation that the turtles will be aliens in his 2013 reboot.
Original Ninja Turtles voice actor Robbie Rist publicly slammed the decision, writing on his Facebook page that Bay was "sodomizing" the first set of films.
On his official forum Shoot For The Edit, Bay wrote: "Fans need to take a breath, and chill. They have not read the script.
"Our team is working closely with one of the original creators of Ninja Turtles to help expand and give a more complex backstory. Relax, we are including everything that made you become fans in the first place. We are just building a richer world."
Bay is producing the film, with Jonathan Liebesman (Wrath of the Titans) in talks to direct.
Teenage Mutant Ninja Turtles will arrive in US theatres on December 25, 2013.
Watch a 1990s Teenage Mutant Ninja Turtles movie trailer below: