Grumpy Cat has died: The internet's favourite moggy passes away, aged 7

Grumpy Cat, the internet-famous feline with the permanently frowning face, has died.

Revealing the news on social media, her family said that they were “unimaginably heartbroken to announce the loss of [their] beloved” pet.

“Some days are grumpier than others,” it began.

Read more: 5 things you didn't know about Grumpy Cat

“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,” they continued.

“She passed away peacefully on the morning of Tuesday, May 14, at home in the arms of her mommy.

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

Twitter users replied to the tweet in droves, with many describing themselves as “heartbroken” after reading the news.

One fan wrote: “I loved this cat. I had the absolute pleasure of meeting her once and I will never forget it. I will never forget the first time I saw her face!

“I learned much from her and am deeply saddened and devastated to hear of her passing. Love you Tartar Sauce! Long live Grumpy Cat!”

Another simply said: “Farewell, our queen.”

Born on 4 April 2012 in Arizona, Grumpy Cat - whose “real” name is Tardar Sauce - rose to fame when Bryan Bundesen, the brother of her owner Tabatha, posted a photograph of her on a Reddit message board.

Before long, her disgruntled expression - which is said to be a side effect of both her underbite and feline dwarfism - had been seen by over one million people, with many claiming that the miserable-looking moggy had been Photoshopped.

She went on to become the face of thousands of memes across the internet, before launching her own website. Now, her visage can be spotted on merchandise all around the world from mugs, trainers and soft toys to calendars and perfume.

Read more: Meet new Grumpy Cat Garfi, the Persian who is furious with everything in life

During her years in the limelight, she accumulated 8.3 million total followers on Facebook, 2.4 million followers on Instagram and 1.5 million followers on Twitter.

Grumpy Cat starred in her own movie in 2014, headlining Lifetime’s made-for-TV Grumpy Cat's Worst Christmas Ever, with Aubrey Plaza providing the kitty’s voice. It wasn’t a hit with critics, with The AV Club calling it “the largest t**d in [Lifetime’s] c**p crown of original programming.”

In December 2015, Grumpy Cat was immortalised at waxwork museum Madame Tussauds in San Francisco.