10 Behind The Scenes Reasons For Harry Potter Character Traits

Now, this technically goes down as a movie mistake, yet it's ultimately in the final film and is an action performed by a character, so we're counting it anyway.

Throughout The Philosopher's Stone, you'll occasionally be able to spot Hermione (Emma Watson) mouthing the words being spoken by Harry (Daniel Radcliffe) and Ron (Rupert Grint).

A feat of magic, you ask? Not quite.

As Watson herself explained in a 2017 interview with Jimmy Kimmel, Hermione's weirdly busy mouth was the result of Watson memorising everybody's lines for a given scene and then mentally reading along with them, yet often unintentionally moving her lips also. She said:

"I created issues because of this. I would ruin takes. [Director] Chris [Columbus] would be like, 'Cut. Emma. You're doing it again. You're mouthing Dan's lines.'... I really loved those books, I really wanted to do my job well, and I kind of overdid it."

Thankfully it's ultimately a more endearing flub than a frustrating one, and one that didn't present itself in future films as Watson became a more confident actress.