British Vogue have landed the cover star every glossy magazine editor has been dreaming of for the past five years.

Yes, Kate Middleton, the future Queen of England, is to grace the June cover of Vogue, a fulfilment of what its editor has quite frankly admitted has been one of her “greatest ambitions for the magazine”.

The photographs were shockingly not taken by Mario Testino but by British photographer Josh Olins, who works frequently with the magazine and was chosen for the landmark shoot owing to the “quiet elegance” and “relaxed understatement” he brings to his work.

The shoot has been shrouded in extraordinary secrecy with astonishingly few staffers brought into the circle of trust by editor Alexandra Shulman and fashion director Lucinda Chambers, who have been patiently wooing Kate for years now.

A rival editor told the Daily Beast: "Hats off to Shulman. That's a proper coup."

Even very senior editors at the magazine contacted by the Daily Beast today said they were in the dark about the June cover.

Chambers styled the pictures, which see the Duchess shot in casual clothes in the Norfolk countryside, near their country home, Anmer Hall.

The June issue – out May 5 – marks the 100 year anniversary of British Vogue, and this is certainly a stylish way to mark that occasion.

The pictures were taken as part of a collaboration between Duchess Kate and the National Portrait Gallery. A portfolio of seven photographs, are to appear with an accompanying article (sources say that although Kate has provided some original quotes for the piece, she has not broken the habit of a lifetime and given a sit-down interview).

The Duchess has been Patron of the National Portrait Gallery since 2012, one of the first gigs she took on after her marriage to Prince William. She studied History of Art at university and has a well-known passion for photography and portraiture.

Vogue has an enviable record of royal portraiture from the days of Cecil Beaton and Norman Parkinson, to Lord Snowdon and Mario Testino.

Alexandra Shulman, Editor-in-Chief of British Vogue commented, “To be able to publish a photographic shoot with HRH The Duchess of Cambridge has been one of my greatest ambitions for the magazine. I’m delighted the Duchess agreed to work with us and the National Portrait Gallery, and as a result of this unique collaboration we have a true celebration of our centenary as well as a fitting tribute to a young woman whose interest in both photography and the countryside is well known.”

Nicholas Cullinan, Director of the National Portrait Gallery, said in a statement, “Josh has captured the Duchess exactly as she is – full of life, with a great sense of humor, thoughtful and intelligent, and in fact, very beautiful.”

A spokesperson for Kate said: "Since 1916, Vogue has been a leading champion of British portraiture. The Duchess was delighted to play a part in celebrating the centenary of an institution that has given a platform to some of the most renowned photographers in this country's history. She is incredibly grateful to the team at Vogue and at the National Portrait Gallery for asking her to take part. She would like to thank Josh Olins for being such a pleasure to work with. The Duchess had never taken part in a photography shoot like this before. She hopes that people appreciate the portraits with the sense of relaxed fun with which they were taken."

Josh Olins said: “It’s a privilege to have been chosen to photograph HRH The Duchess of Cambridge for the Centenary issue of British Vogue and an honour that two of those portraits will hang in the National Portrait Gallery in London. This was the Duchess’s first sitting for the magazine and she was a joy to work with, a natural. I am incredibly grateful to Alexandra Shulman for placing her faith in me for such an important and historic assignment.”