Kate Middleton Post Pregnancy Pics: Duchess Of Cambridge's Dramatic Weight Loss 6 Weeks After Delivering Baby Number Two

Kate Middleton is back at wearing skinny jeans six weeks after giving birth to Princess Charlotte, her second child with Prince William.

An insider from People credited this amazing change to a popular but pricey trainor, breastfeeding and the everyday old-fashioned dieting and aerobic exercises that works well with the 33-year old duchess.

The insider said that Middleton has been keeping the 'super-discreet' London-based trainor since her pregnancy and has been keeping an eye on her body.

"It's a lot of money, but you get a lot for the price," the source said.

Like other celebrities, Mila Kunis and Scarlett Johansson, Middleton also attributed her healthy weight loss to breastfeeding, Yahoo News said.

Being a picky, clean-eater, the 33-year old mother has also shifted to organic fruits and vegetables. She also subsists on lean meats.

"The food is very elegant and actually feels like food you would eat at a restaurant. The whole program is very sensible - it's not fad-based and is really focused on your overall health and well-being," the source said.

Meanwhile, news outlets like Mail Online cannot help compare Kate Middleton's post-baby body with the Queen's granddaughter, Zara Phillips who is spotted for her bulging 'mum tum.'

The Royal family member was seen wearing a fitting lemon shift dress at the Royal Ascot this week that emphasizes her bulge speculated to be caused by a possible second pregnancy.

However, Phillips later confirmed that she not expecting a second sibling to her 18-month old Mia.

"Zara is not pregnant - her plans remain the same in terms of preparation for Rio 2016," a spokesperson said.