Director James Marsh‘s new film The Theory Of Everything depicts the early life of scientist Stephen Hawking, played by Tony award winning actor Eddie Redmayne. The biopic spans many years of Hawking’s life, from his days as a student seeking his PhD in Physics and his diagnosis with ALS and fatal prognosis to his global recognition. It’s based on a book by Jane Hawking, Stephen Hawking’s first wife. After his diagnosis with ALS at age 21, Hawking’s has said his engagement gave him “something to live for.”

Hawking has seen an almost-finished version of the film, and liked it so much that he donated his real “voice” — the program he uses for speech — to the film. “The voice you hear in the latter part of the story is in fact Stephen’s actual electronic voice as he uses it and that was quite an interesting flavor [sic] that we got from Stephen after the film was pretty much cut and finished,” Marsh told DeadlineThe Theory Of Everything will debut next month at the Toronto International Film Festival.