The internet's most popular cat and one of its first viral memes, has died aged 7.

The grumpy sensation's family announced her death on Twitter on Friday.

"We are unimaginably heartbroken to announce the loss of our beloved Grumpy Cat," Tabatha Bundesen, Grumpy Cat's owner, said.

The cat from Arizona had "helped millions of people smile".

"Despite care from top professionals, as well as from her very loving family, Grumpy encountered complications from a recent urinary tract infection that unfortunately became too tough for her to overcome," Grumpy Cat's family said in a statement on Friday, May 17, on her Twitter. account, which has amassed more than 1.5 million followers. "She passed away peacefully on the morning of Tuesday, May 14, at home in the arms of her mommy, Tabitha."

The statement continued, "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. Her spirit will continue to live on through her fans everywhere." The tweet was captioned, "Some days are grumpier than others."

Grumpy, whose real name was Tardar Sauce, went viral in 2012 after photographs of her sour expression emerged online. Her image quickly spread as a meme.

According to owner Tabitha Bundesen, her facial expression was caused by feline dwarfism and an underbite.

Grumpy Cat travelled the world making television appearances and in 2014 even starred in her own Christmas film.

Madame Tussauds in San Francisco unveiled a waxwork of her in 2015.

This cat will be missed.