When you think of the Boy Who Lived, you probably think of round glasses, a bedroom in a cupboard under the stairs and a lightning bolt scar.
But it turns out everything we thought we knew about Harry Potter's legendary scar might actually be a lie.
Some very dedicated Harry Potter fans are convinced that the jagged red mark on Harry's forehead might not actually be a lightning bolt, but something else entirely.
And it's causing quite a stir on social media.
The Twitter account, Today Years Old, has made this bold claim, after discovering more about the killing curse which produced the scar.
In a post, they wrote: "Did you know Harry Potter's scar isn't a lightning bolt, but actually the hand motion to cast Avada Kedavra."
Alongside this, they shared a photo of Harry's scar and a screenshot of an entry from Harry Potter Wiki about the unforgivable spell.
The screenshot shows the hand movement needed for casting the curse - which is the same shape as Harry's scar.
This would make sense as it is the same spell that Voldemort used to kill Harry's parents - resulting in his scar.
The tweet quickly garnered a lot of attention, with more than 2,000 likes and hundreds of shares.
People couldn't hide their shock at the revelation.
One person replied: "I'm not even a Harry Potter fan and I'm surprised af."
Another said: "Woah."
A third added: "It all makes sense now."
"I actually didn't know that," commented a fourth. "I loved the movies but never read the books or really geeked out on it."
Someone else claims they did know this and it's actually both a lightning bolt and the symbol for the hand movement.
J.K. Rowling has yet to respond to the tweet and confirm whether the post is correct, so until that time, we'll keep looking out for more interesting fan theories.
