Kate Middleton danced during 40th birthday photoshoot - photographer reveals

The Duchess of Cambridge also wore "little makeup"

The photographer who captured the stunning portraits of the Duchess of Cambridge for her 40th birthday has revealed secrets from their photoshoot at Kew Gardens.

In an interview with Italian newspaper, Corriere della Sera, Paolo Roversi revealed how he persuaded Kate to dance an "accelerated waltz mixed with a pinch of rock 'n roll" after she donned an organza Alexander McQueen gown that reminded him of a "classical ballerina".

The pair first met for tea and biscuits at Kensington Palace in November and the Duchess was initially apprehensive about the photoshoot.

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WATCH: Kate Middleton's milestones as she celebrates 40th birthday

Paolo, who has worked with the likes of supermodels Kate Moss and Naomi Campbell, said: "But at first the Duchess was apprehensive. Every day she is machine-gunned by photographers but not used to posing; knowing my photos with the models she was a bit fearful in facing a real session, which then required about four hours of work. But once she started it would be very easy, I reassured her."

The Duchess also personally thanked fans for their birthday wishes

The Duchess and Paolo drew inspiration from 19th century photography, which was the focus of Kate's undergraduate thesis at the University of St Andrews.

One of the three images released shows the Duchess smiling directly at the camera in a one-shouldered red gown by wedding dress designer, Alexander McQueen.

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The images were taken at Kew Gardens in November

She is also shown in two black and white photographs, one shot in profile, reminiscent of royal portraits taken by Cecil Beaton, and another close-up showing her beaming at the lens.

"In the end I wanted to take pictures in motion, so with that wonderful wide skirt I made her dance in front of my lens, a kind of accelerated waltz mixed with a pinch of rock 'n roll," Paolo said.

The series of images are likely to remain private, however.

The photographer said that in December the photographs were whittled down to 70 from a selection of 250, and revealed how he captured the Duchess in natural light, with "little makeup, no hairstyle, simple earrings, a ring…The focal point of Kate's face is her gaze and smile".

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