The 33-year-old English actor plays Newt Scamander, the wizarding world's leading magizoologist, reported Entertainment Weekly.
"Like many people, I read those books, I watched those films, and became completely intoxicated by JK Rowling's world. The idea of getting to tiptoe into it felt truly exciting. I hope it's going to be quite a ride," Redmayne said.
In the story his character is on travel to find and document magical creatures.
Written by Rowling and directed by Potter franchise veteran David Yates, the shooting of the film began last month at the UK's Leavesden Studios, where all the eight Harry Potter movies were shot.