Katy Perry is mourning the loss of her pet cat, Kitty Purry

Fifteen years ago, a very special cat arrived in Katy's life, proving that the best gifts are the ones you don't expect.

An unexpected gift

"Kitty Purry crawled through my then-boyfriend's window 15 years ago, fully pregnant and seeking shelter," posted the singer.

The two became best friends, and Kitty travelled the world with her superstar cat mum. She even appeared in the music video for one of Katy's biggest hits - I Kissed A Girl.

But Kitty's time in the spotlight came to an end last week after she passed away from old age.

Katy posted the sad news on Instagram, paying a heartfelt tribute to her four-legged friend. She wrote:

"Sadly, Kitty completed her 9th life last night. I hope she rests in salmon fillets and tuna tartare way up in catnip heaven. Kitty, thanks for the cuddles and companionship along the way."

Kitty certainly left her mark on the world, including two litters of kitties who all went on to find loving homes.

Rest in peace Kitty

Despite the tragic news, there's still lots to look forward to in the Perry household. The singer is currently expecting her first child with husband Orlando Bloom.

It's just a shame that Kitty will never get to meet her human sister.