When it comes to Harry Potter's appearance, dedicated fans of the series have no doubt noticed a major discrepancy between the books and the movies. And it has a little something to do with "his mother's eyes."

In the books, The Boy Who Lived is described as having "bright green" eyes—but actor Daniel Radcliffe's naturally blue eyes are the ones that we saw in all the movies. Why did author J.K. Rowling and the movies' producers decide to ignore this major detail?

As it turns out, the exact color of Harry's eyes was not as important a detail as some fans may think. Rowling only asked the producers that Harry's eyes be the same color as his mother, Lily's, but she never stipulated that the color had to be green.

This must have been a huge relief for Radcliffe, who had an adverse reaction to the green contacts the filmmakers originally wanted to use to give him the eye color the books had promised. It probably didn't hurt that Radcliffe's natural eye color was part of what made producer David Heyman notice him, and push him to audition for the role.

"There sitting behind me was this boy with these big blue eyes. It was Dan Radcliffe," Heyman later said of the first time he met Radcliffe at a theater. "I remember my first impressions: He was curious and funny and so energetic. There was real generosity too, and sweetness. But at the same time he was really voracious and with hunger for knowledge of whatever kind."

Following their meeting, Heyman convinced the then-unknown child actor to audition for the role. The rest, of course, is history.