Kim Kardashian West uses a waist trainer to "emphasise" her butt.

She said: "Kim uses the trainer to lose weight but also to maintain her shape.

"It slims the waist which emphasises the bottom too. She's obsessed with it."

According to Premaddona, Kim can expect to lose up to two inches a week if she wears the garment for six hours a day.

She explained: "The waist trainers are made from a combination of Lycra, spandex and latex and they work by pulling you in around the middle.

"The material makes you sweat more around your waist - meaning you lose inches in that specific area. It gives you that hourglass shape."

And 34-year-old Kim - who has 21-month-old daughter North with husband Kanye West - is so dedicated to using the corset she carries one in her handbag wherever she goes.

Her friend added to Grazia magazine: "Kim carries a waist trainer in her handbag everywhere she goes.

"She wears one in the gym, which means she gets quicker results, or when she's running around ahead of photo shoots.

"You can wear it under dresses on the red carpet too. Some customers even sleep in it."