Eddie Redmayne was cast in 'Fantastic Beasts and Where To Find Them' because he can bring "heart and compassion" to his characters.
Redmayne portrays magizoologist Newt Scamander in the upcoming 'Harry Potter' spin-off and was the first choice for the role.
Producer David Heyman said: "Newt is someone who can communicate better with his creatures than he does with people. He's a Brit who finds himself in the US and the American magical universe is different to the British one.
"Eddie was our first choice. He's very good at playing characters that are out of step, as it were, and bringing to them a real heart and compassion. He has a desire to bring truth to every moment. He's very charming and appealing to men and women alike. And he's a timeless actor, so he fits perfectly into 1920s New York."
Eddie is joined in the film by Colin Farrell, Ezra Miller, Jon Voight, Samantha Morton and Ron Perlman and creator J.K. Rowling - who also wrote the screenplay - approved of all the casting.
Discussing how hands-on she has been on the project, David told Total Film magazine: "Jo was on set and has been an incredible support to us.
"We'd run concepts by her, she'd give her thoughts and we'd adjust accordingly. She certainly was aware of all the lead casting choices before we finalised them."