"I hope she rests in salmon fillets and tuna tartare way up in catnip heaven," Perry wrote.

It's a very sad day for Katy Perry, who is mourning the death of her beloved cat, Kitty Purry.

The 35-year-old pop star revealed the upsetting news in an Instagram post on Sunday (April 18), writing that Purry had "completed her 9th last night" and gone to "catnip heaven."

"Kitty Purry crawled through my then-boyfriend’s window 15 years ago, fully pregnant and seeking shelter," wrote Perry, who is currently pregnant with her first child. "Two litters and many moons later, this street cat became a lovable mascot to many."

The "Never Worn White" singer's post included several throwback photos of herself cuddling with Purry and even one of Perry doing FaceTime with her adored pet.

"Sadly, Kitty completed her 9th life last night. I hope she rests in salmon fillets and tuna tartare way up in catnip heaven," she continued. "Kitty, thanks for the cuddles and companionship along the way. Big thanks to my brother David and @garethwalters for being great co-parents."

Numerous celebrities responded to Perry's Instagram post and shared their condolences for her loss, including reality TV star Kris Jenner, fashion designer Jeremy Scott and singer Sarah Hudson.

Over the years, Purry has become a celebrity in her own right, having appeared in her owner's 2013 lyric video for "Roar" and being nominated for best celebrity pet at the Teen Choice Awards in 2009.