Hello Kitty is not a cat!
In fact, she's a human schoolgirl who lives outside London, has a twin sister and a pet cat of her own.
For 40 years, fans of Hello Kitty have believed that her round face, button nose, pointy ears and whiskers marked her out as a feline; and it seems we weren't the only ones to be taken in by the whiskered school girl's deception.
Christine R Yano, an anthropologist from the University of Hawaii, has spent years studying Hello Kitty and even she thought Kitty was a cat.
Christine was preparing a script for a presentation at a Hello Kitty exhibition to celebrate the character's 40th birthday, when she made the startling discovery.
A draft version of her speech was being checked over by officials at Hello Kitty creators Sanrio, who 'very firmly' pointed out that Hello Kitty is not a cat, but a girl.
"That's one correction Sanrio made for my script for the show, Hello Kitty is not a cat, " Christine told the LA Times.
She's a cartoon character. She is a little girl. She is a friend. But she is not a cat.
"She's never depicted on all fours. She walks and sits like a two-legged creature. She does have a pet cat of her own, however, and it's called Charmmy Kitty."
Sanrio didn't give an explanation for Hello Kitty's cat-like appearance, but they did say that she has a full back story.
"A lot of people don't know the story and a lot don't care," added Christine. "But it's interesting because Hello Kitty emerged in the 1970s, when the Japanese were into Britain.
"They loved the idea of Britain. It represented the quintessential idealised childhood, almost like a white picket fence. So the biography was created exactly for the tastes of that time."
More Hello Kitty facts that you probably didn't know
Her full name is Kitty White.
Her parents are called George and Mary White.
She has a twin sister called Mimmy.
She is five apples tall.
She has type A blood (!!)
She is a Scorpio, born on November 1.
A seal lives in her backyard.
She has traveled into space - a 4cm tall hello Kitty figure is aboard the Hodoyoshi-3 satellite and is positioned so that she can see earth through the craft's window!