Grumpy's real name is Tardar Sauce and boy does the internet love this saucy little minx. She's even made her first appearance on TV! Watch the video above.
Countless internet memes parody this sad squishy face that has almost hit 480,000 Facebook likes.
There are also countless Grumpy Cat Twitter profiles, but the official account has just under 38,000 followers That's almost as much as a small time TV host but not nearly as many as a Kardashian.
So how did this happen?
"Once you get enough votes to get on the front page of Reddit, you're off and running," Matt Silverman from Mashable explained to The Miami Herald.
"I always think about virality in concentric circles, with The Today Show being the outermost circle," he said in explanation of Tardar's recent appearance on the US talk show.
"Once it gets to The Today Show, then my mom knows about Grumpy Cat," he said.
Relive this cat celebrity's TV appearance in the video above and check out more cat celebrities in the slideshow below.