Pippa Middleton, sister of Catherine, Duchess of Cambridge has revealed the secret behind her greatly toned body in a testimonial at Parson's Green Pilates Studio in London.

The English socialite and party-planner, who has been at the center of media attention since the Royal Wedding, claims that a weekly session of Pilates has helped her immensely to improve her posture and muscle tone.

This gentle form of fitness system developed in the early 20th century by Joseph Pilates in Germany involves slow, controlled movements to work the core muscles found in the tummy and the back.

In an endorsement for the London-based studio, the 27-year old mentions that As someone who is always 'on the go', Pilates has been a wonderful escape from my busy lifestyle in London. Whether it's 7am in the morning or 7pm at night I always leave feeling calm, refreshed and invigorated. Over the past few months I have noticed a huge difference in my core strength and posture and couldn't recommend Margot more highly as an instructor. From breathing techniques, muscle toning to overall flexibility and relaxation, my Pilates sessions has become something of a weekly necessity that keeps me fit, happy and energized.