Grumpy Cat, the cat that became an Internet sensation because of her permanent scowl, has died.

Her owners shared the sad news on Facebook this Friday, writing: "Some days are grumpier than others."

It was explained Grumpy Cat, real name Tardar Sauce, passed away last Tuesday due to urinary tract infection-related complications.

"Besides being our baby and a cherished member of the family, Grumpy Cat has helped millions of people smile all around the world, even when times were tough," the post read. "Her spirit will continue to live on through her fans everywhere."

Grumpy Cat first went viral back in 2012 thanks to her seemingly permanent cranky expression, said to be caused by feline dwarfism and an underbite.

She is one of the most followed animals on social media, boasting more than 8.5 million followers on Facebook alone.

Her popularity inspired countless memes, a Christmas TV movie, a series of books, and various other merchandise.