‘When we work out we don’t just do a couple of moves,’ says pilates instructor Mari Winsor.

‘It’s at least a half an hour of working out.

‘You have to learn how to not just тιԍнтen up your tummy but actually pull your tummy in to your lower back as much as you can. Just doing 40 crunches a day isn’t gonna do it for you,’ she says.

The Los Angeles-based fitness guru revealed Miley has recently installed a studio in her own home so she can sculpt her body every day, and is especially pleased with the result Mari’s workout regime has had on her lithe limbs.

She told People magazine: ‘I gave her those legs. She’s always going to have those long gorgeous legs. We just toned and firmed in all the right places.

‘She wants to be healthy, she wants to have good abs. It always makes her feel better and clearer when she works out.’

Greg Small, spokesperson for Register of Exercise Professionals (REPs), says you need to do more than sit-ups to achieve a fit physique.

‘While it’s great that Miley Cyrus has attributed her abs to a daily exercise regime, there is not much benefit to be had from doing daily crunches alone,’ he says.

‘Spot reduction is something of a myth and it is absolutely essential that any exercise regime incorporates a certain degree of variety and balance in exercise selection.

‘If you practice crunches on a daily basis, your body will quickly adapt and stop responding to the exercise stimulus, thus making the practice somewhat useless.’

Lorna Driver-Davies, Nutritional Therapist at The Nutri Centre, added: ‘Miley’s physically demanding job in the spotlight requires her to be fit and active, so it’s great to see that she enjoys exercising and working out.

‘She has the luxury of being young which can result in having a faster metabolism and a team of expert nutritionists and dieticians to hand to help her achieve such a slim figure.

‘In addition to this, some time ago she announced that she is gluten intolerant. For those who suffer with this condition, excluding gluten containing products may reduce abdominal bloating. By cutting this food group out, Miley’s stomach would also appear flatter if previously gluten was causing her a problem.

‘Coupled with her hectic lifestyle in the spotlight, I’m sure her nutritionists recommend she eats lots of B6 rich foods, such as dark green leafy vegetables, lean protein and good carbohydrates such as quinoa and oats to help boost her energy levels.

‘Perfect for someone with a physically demanding lifestyle.’