KUALA LUMPUR, Nov 21 — An adorable black-and-while tubby tabby dubbed Britain’s fattest cat has been put on a strict diet after she shocked rescue staff with her unusual weight.

The four-year-old Paisley weighs in at a whopping 9.5kg, double the weight of a healthy cat.

According to Metro UK, the chubby feline was sent to the rescue home after her owner couldn’t cope anymore.

It was also reported that staff at the Cats Protection’s National Cat Adoption Centre in West Sussex have to help her clean herself as she has become too big to do it by herself.

The centre’s deputy manager Tania Marsh said she was shocked when she first saw Paisley.

"When I saw her, it took my breath away. She’s the fattest cat I’ve ever seen.

"I’ve been with Cats Protection for 13 years and we get some cats on the larger side sometimes but nothing of this extent,” she added.

It's thought that Paisley’s massive bulk comes from being overfed by her previous owner, combined with a lack of exercise and poor diet.

Marsh also confirmed that Paisley’s former owners gave her up for adoption last month and she has already found a new owner.

Paisley is now on a stern vet-prescribed diet to help her slim down in a controlled way, which has already showed some results.

Despite the positive progress, Marsh said Paisley was still at risk of developing diabetes and needed to continue her diet.

"When Paisley goes to her new home, she'll have to maintain the diet. No treats are allowed,” she added.

Paisley’s food is specially formulated to have less calories and it allows her to feel full for a longer period of time.

"Regular checks with the vet will also be needed as we need to make sure she doesn’t lose weight too quickly, otherwise she could develop a fatty liver,” said Marsh.