He explains, "This is a woman who decided to persevere... She was on welfare... and she really hit rock bottom."

Poppy Montgomery, who has adopted a British accent for the role and will even wear blue contact lenses to resemble the writer, admits she's a big fan and wouldn't know what to do if Rowling decided to pay a visit to the set.

She tells Access Hollywood, "I'd turn into a puddle of water."