Is Rupert the world's mightiest moggy? Mammoth cat weighs in at 20lb... and he's still growing

At three times the size of the average cat, most would think giant pet Rupert has done enough growing for now.

But the super-sized feline, who at 20lbs (9kg) could claim to be one of the world's biggest cats, is only half grown and set to gain more weight.

The giant breed Maine coon is only half its possible size at nearly three years old, and is expected to put on another 11lbs.

Larger than life: Natalie Chettle holds her mother's giant cat Rupert over her head

Not the average cat: Rupert, who at 20lbs is expected to put on further weight, tries to make a new friend

A three-time cat of the year in his native Australia, Rupert is said by cat competition judges to be among the biggest Maine coon domestic cats they have ever seen.

Cat competition judge Lesley Morgan Blythe said: 'He's a mega, monster cat and still yet to fully fill out.

'He's bigger than the biggest maine coon I've seen. And he's probably only half grown at two.'

Rupert's owner, Kyra Foster, said: 'He is particularly majestic looking with his long hair adding to his magnificent, wild look.

Rupert is a Maine coon cat, a breed which are known for their larger bone structure

Prize-winning: Rupert is a three-time cat of the year in Australia, and is said to be one of the biggest domestic cats in the world

'People are blown away when they come to him.'

Maine coon cats are known as the breed which produced some of the biggest domestic felines.