Daniel Radcliffe and J.K. Rowling talk about how "Harry Potter" changed their lives in a special feature on the "Harry Potter and the Deathly Hallows -- Part 2" Blu-ray and DVD.

Daniel Radcliffe was once allergic to “Harry Potter.”

In a never-before-seen conversation with “Harry Potter” author J.K. Rowling featured in the “Harry Potter and the Deathly Hallows – Part 2? Blu-ray and DVD, on sale Friday, Radcliffe reveals that he had an allergic reaction to his first pair of Potter glasses.

“It was brilliant because we put the glasses on and eventually we realized that I was allergic to them,” he said. “I was actually allergic to the Harry Potter glasses. Because I had these two rings of whiteheads and spots that had come up around my eyes and it took us a week to realize that it was actually the glasses.”

“It’s lucky neither of us believe in signs isn’t it?,” Rowling laughed. “You were meant to be.”

Radcliffe and Rowling’s 53-minute long conversation is one of more than a dozen extras featured on the disc. Their sit-down, filmed in London in 2010, chronicles how the iconic film franchise changed both their lives (after Radcliffe got a new pair of glasses, of course).

Also a must for “Potter” fans: The “Blowing Up Hogwarts” special feature that takes an in-depth look at how Harry Potter’s school came crumbling down.