The duchess wore a yellow broderie anglaise sundress on her recent South Pacific tour, and it has now emerged it was a piece specially-commissioned by Queen Elizabeth's tailors, based on the royal's own ideas.

A source told Grazia magazine: "This dress was a piece commissioned by Kate. She likes to have a few pieces that are one-offs and that she has had some input in, so she asked the queen's tailors for some help.

"They worked on it together after she went to them with ideas of colour, fabric and style."

Catherine - who was known as Kate Middleton before her wedding to Prince William - regularly wins praise for her fashion choices, and was recently named one of the best-dressed royals by Vanity Fair magazine.

They said: "The former Kate Middleton is prim, proper, and infuriatingly dazzling, thanks to a year-round tan, bouncing blow-outs, some better version of Bobbi Brown than the rest of us have, and a decidedly un-English smile. For big events, the mice and bluebirds put Kate in the best British designers as befits a future queen of England, including Alexander McQueen, Christopher Kane, Burberry, and country staple Barbour."