Daniel Radcliffe and Karan Soni have revealed that the young cast of Harry Potter all had to wear prop teeth while filming the first few movies. Author J.K. Rowling has been revealing Hogwarts secrets for years on social media and Radcliffe just let a pretty good behind-the-scenes tidbit out. However, Soni was ready to reveal something else about working on the Harry Potter movies and it made Radcliffe pretty nervous, so we're all wondering what that behind-the-scenes secret is all about.

When filming began on the first Harry Potter movie in 2001, Daniel Radcliffe was just 11-years old and the rest of the cast was the same age or younger. Kids at that age lose teeth, so crew members had to think of a solution to the widespread problem of keeping continuity. In a new interview promoting their new show, Miracle Workers, Daniel Radcliffe and Karan Soni revealed how they got around that problem. Soni explains.

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"When they were doing the earlier movies, because their teeth were falling out, they would have a cast made of all their teeth. So that if one fell out, they could have a prop tooth put in. Just so they could keep filming."

Daniel Radcliffe nodded in agreement when Karan Soni was telling his behind-the-scenes Harry Potter story. Radcliffe added, "Cause you've got a set full of twenty 10-year-olds... they would cast everyone's mouths." That actually makes perfect sense, and sounds like a relatively easy, albeit expensive, process to go through. Maybe Hermione's parents took care of the cost. Obviously, the cast grew up in the later movies, so their fake teeth were no longer needed.

This is a far better Harry Potter secret than the recently revealed nugget of information that Pottermore gave fans a few months back. Apparently, Hogwarts didn't have plumbing for quite a long time, so everybody would do their business wherever they were standing and cast a spell to bring the waste somewhere else. Harry Potter fans were not happy to learn this, especially since there is no 'disappearing' spell. In the Harry Potter universe, matter can not be created or destroyed, so the waste would have gone somewhere. Perhaps to a cess pit? Who knows, maybe J.K. Rowling will introduce the history of Hogwarts plumbing in the next Fantastic Beasts installment. The whole teeth thing is much better information than the whole plumbing fiasco.

Karan Soni also revealed that for a while, he thought that he was going to be cast as the titular character in Harry Potter, which would have had Daniel Radcliffe's life turn out much differently. In other Potter news, Radcliffe revealed that he has been to the Wizarding World of Harry Potter and that he enjoys it. However, he went on a private tour before it was open to the public because he felt that it would have been too weird to go with the general public. Plus, it probably would have caused pandemonium, so it's for the best that he was able to experience it privately. You can check out the big teeth reveal about the Harry Potter kids in the interview below, thanks to The Hollywood Reporter Twitter account.