Cute MicroBoo, a falabella, is the same size as a bowling pin, and was born two weeks ago to stunned owner Jen Baldwin-Murphy - who is famed for breeding tiny horses.
The black-and-white foal is the sister of MicroDave, who shot to fame after he was born measuring just 11 inches - smaller than a 2 litre bottle of Coca Cola.
Owner Jen Baldwin-Murphy is a show-horse trainer by trade, but admits having a soft spot for pint-sized ponies.
The stables in Tonbridge, Kent, which house the tiny animals have been flooded with visitors since the birth of the tiny horse.
Jen, 50, said: “She was born about 15 inches; she’s up to about 16 inches now at a couple of weeks old.
“They’re a lot cheekier than the big horses.
“I suppose with the big horses they have to be well-behaved because they can be dangerous.
“Whereas with the miniatures you sort of forgive them because they’re just so gorgeous.”
“She’s very playful and very inquisitive.
“If you call her, she’ll come trotting up to you, which is quite unusual for a two-week-old foal.”
MicroBoo’s mother, Rockstar, is a 33 inch Falabella who has participated in and won many championships throughout the UK.
The tiny horses average between 28 and 34 inches, and have been bred since the mid-19th century.
Jen added: “Falabellas are quite rare still in this country, and there’s a big following of miniatures as they get more popular.
“They’re like toy dogs - they have a cult following.
“I normally show big horses and do dressage with them, but a few years ago when I was looking for my next big star, my friend sent me a picture of MicroDave as a foal and I loved him.
“They’re so addictive, you can never just have one, and it’s grown from there.
“I do county shows with the big horses but I take the miniatures along as a bit of fun, they’re such characters.”
Jen says MicroBoo is very sociable, and bucks the trend of the stereotypical shy persona which is characteristic of her species and age.
But she added that naughty MicroDave steals most the limelight.
Jen said: “They’re quite spoilt, and too cute to tell off.
“MicroDave is an absolute brat.
“If he was a child he’d be Macauley Culkin because he’s a child star gone rogue.
“I had to stop all the paparazzi in the end because he was just getting naughtier and naughtier.
“He’s a complete famous brat and he knows it.
“He’s the sort of person who would say: ‘Do you know who I am?’”