The 42-year-old’s dog Rolo suffocated – she believes it died instantly – after getting stuck in the chair’s mechanism while she was out the room.
It was her younger daughter Bunny, five, who made the grim discovery.
Katie rang the breeders who “gifted” her the pup and told them she was packing bags when it died.
A spokesman for JRC Bullies told us: “We are heartbroken that this has happened as we told Katie not to leave a small puppy on its own.
“We can’t believe that the puppy was left unattended as we had left strict instructions.”
Katie’s spokesman said it was a “tragic accident”. But fans urged the RSPCA to investigate her after another animal died in her care.
In February, Katie’s Alsatian, Sparkle, died after being hit by a car. Her other dog, Queenie, died after being run over by a pizza delivery van. One of her horses was previously killed in a crash.
An RSPCA spokesman said: “This is a very sad situation. Due to legal reasons we are unable to discuss if we have received complaints and what action may or may not have been taken.”
Elisa Allen, director of animal rights group PETA, said: “Katie must not be allowed to acquire any more animals. At least three dogs and one horse have died on her watch in the last few years alone.
“Her attitude is costing wonderful animals their lives, so PETA urges her – and anyone else unable to provide animals with appropriate care – to fill their homes with cuddly toys instead.”
Last night, Katie said: “It’s nobody’s fault and something that happened tragically. We are all devastated about so instead of pointing fingers think of how we are all feeling so respect us all”.
Princess posted: “RIP baby boy. I love you so much. You meant everything to me. Miss you.” She said in an online video: “I’m absolutely devastated. I can’t even speak properly about it.”