Cheryl Cole lost weight with the Dukan diet and a stint in boot camp

Cheryl Cole has reportedly lost weight with the Dukan diet and a stint in boot camp.

The Girls Aloud singer allegedly put on weight during her stint on the US X Factor where she apparently was homesick and spent her evenings in her LA hotel watching movies and taking comfort in Hobnobs biscuits and junk food.

However, since returning home following her departure from the talent show she has been working hard to get her body back in shape.

It is rumoured that she has been following the Dukan diet plan and she also spent seven days at a luxury UK fitness retreat two weeks ago.

Cheryl spent four to six hours a day exercising during her time at the boot camp.

She also had treatments, including thalassotherapy pool sessions and detoxifying seaweed wraps, which promise to melt inches from your body.

A source told Now magazine: "Cheryl Cole's been exercising like a demon because she's determined to look her best for Ashley Cole.

"He always tells her he likes her looking `fit' and that was motivation enough."

Kate Middleton's mom's 56-pound weight loss spurs popularity of Dukan Diet

Kate Middleton's mother, Carole Middleton, lost 56 pounds last year on the controversial high-protein, low-carb Dukan diet, catapulting sales of the French diet book in the U.K.

“I’ve been doing it for four days and I’ve lost four pounds,” the former British Airways flight attendant said in an interview last year.

Carole, 56, began the diet a month before her daughter Kate, 29, announced her engagement to England's Prince William, 28.

Since its UK launch in May 2010, the Dukan Diet book has sold over 250,000 copies in England, thanks in large part to Carole's indirect promotion.

The Dukan Diet will be released in the United States and Canada on April 19.

Kate Middleton and Mom Follow Dukan Diet

Several reports claim that Kate Middleton and her mother, Carole Middleton, are both following the Dukan diet. The Daily Mail reported in November that Carole lost four pounds in just four days during the first phase of the diet created by Pierre Dukan. The diet involves four stages, the first of which predominately consists of lean protein.

However, there has been much concern over Kate Middleton's apparent weight loss. Rumor has is that she has been following the same diet plan as her mother although the matter has not been publicly confirmed. "It's a hugely private matter," a press aide told the Associated Press. The 5-foot-10 future Princess was once reported to weight 120 pounds, which is on the low end of what might be considered healthy.

Among a group of well-wishers gathered in Belfast, Northern Ireland, one woman told Kate "not to lose any more weight." Kate replied that it was all part of the wedding plan.

The Dukan diet has received much criticism, and is often compared to the Atkins diet of France. Many argue that the diet promises a quick fix that eventually leads to gaining the weight back, while others argue that it's expensive and bad for the liver.