Cox was producers' first choice for the part, but his voice didn't fit the live-action lion.
Producer MARK JOHNSON says, "We knew instantly we had found our mane man."
Neeson had never read the Narnia books, despite growing up just 30 miles away from author CS LEWIS, and called on his 10-year-old son Michael to coach him about the story.
He says, "I wasn't aware of the books. He (Michael) instructed me about Aslan... I feel kind of ashamed. They are such beautiful books."