Harry Potter was almost recast in the middle of the franchise. Daniel Radcliffe's parents initially turned down the role when it was a seven-film deal and filming in Los Angeles.
Some American actors tried their luck and even offered to work for free as long as they could act. Professor Snape in all his scary presence didn't just pop out of author JK Rowling's head, she had a very real inspiration for the character in the form of her former chemistry teacher John Nettleship.