Five fun facts
1 HER FACE IS FOR REAL
When its photos first emerged, many thought that Grumpy Cat's frown was doctored. But subsequent video clips and real-life appearances have proven that her facial expression is real.
2 IT'S NOT GRUMPY
Far from being perpetually cranky, Grumpy Cat's small stature and signature mean look are a product of feline dwarfism. Its owner, Ms Tabatha Bundesen, said in an interview that Grumpy Cat's brother, Pokey, is the grumpy one.
3 IT'S A PUBLISHED AUTHOR
In news that will enrage starving authors the world over, Grumpy Cat has two book titles to its name.
The contents of the books range from disgruntled life tips to discouraging words, so optimists beware.
One of the books, Grumpy Cat: A Grumpy Book, made it to No. 7 on the New York Times bestsellers list.
4 IT HAS AN AGENT
Grumpy Cat is managed by Mr Ben Lashes, who works as an Internet meme talent manager.
Yes, that's an actual job.
Mr Lashes also manages Grumpy Cat's other Internet contemporaries, including Nyan Cat and Keyboard Cat, and is responsible for snagging the movie deal for Grumpy Cat.
5 IT'S PHOTOGRAPHED ONLY ONCE A WEEK
That's because its human family, the Bundesens, want to keep her life as normal as possible. Handling by strangers is also limited.