THANKS to the Kardashian clan, bums have never been so en vogue.

Jennifer Lopez may have been shaking her butt since the late '90s, followed by Bootylicious Beyonce but it is Kim and her sisters who have taken bountiful backsides to the next level.

In their quest for a shapely derrière, women from Bolton have been flocking to a new Booty Shaper exercise class.

The 30 minute workout has been running for about six weeks at Vintage Studio, Knowsley Street, and is already a hit with members.

Fitness instructor Kerry Harrison, aged 34, who lives in Farnworth, said: "It's a full glute workout and a bit of legs.

"You do feel it in the class, it does burn.

"It is what it says on the tin.

"It's really popular with women although it's good for men as well.

"There's no reason why men shouldn't do it. Your glutes and your legs are your biggest muscle group.

"You burn a lot of calories.

"They love it.

"The class is more or less full every week."

People regularly ask Kerry, who has been a fitness instructor for five years and body building for 18 months, how to sculpt their behind.

She said: "People are more aware of their health and fitness and sculpting their bodies. It's a lot more about what you have got to eat rather than being stick thin and having no shape.

"80% of the finished product is food, it's a lot more important than the exercise.

"People think it's about using creams but it's exercise and good food and water.

"Anybody, any age can change their body with exercise and food."

Reality star Kim K's biggest asset has been the topic of conversation since she found fame, but what does Kerry make of the look — along with sister Khloe's — that seems to influence an army of fans on Instagram and Twitter?

She said: "I think that's a bit extreme but when people have got money, they are allowed to do that. 

"I don't think people should look at them and think I want to be like that.

"Everyone has got different bodies and they should try and make the best of what they have got."

Kerry regularly gives tips and advice to people, including finding time for exercise in the most unlikely of places, such as doing squats while waiting for the kettle to boil.

She said: "It's massive, in the bodybuilding industry, squats are like religion."