Secrets from the Queen's Closet: The Hidden Meanings Behind Her Amazing Clothes

No. 1: She always wears British designers

Photo: Popperfoto/Getty Images

Loyal to the talent in her country, Queen Elizabeth has only publicly worn British designers throughout her record-breaking reign.

That is just one of many secrets unearthed as the Queen, 90, throws open her incredible closet in a ground-breaking exhibit at Buckingham Palace that opened on July 23.

“She has been steadfast in her support of British design. That is quite something over such a period of time,” curator of Fashioning a Reign, Caroline de Guitaut, tells PEOPLE. “Her unswerving support of British design is very much a theme of the exhibition and giving visitors an understanding of what it takes to make couture clothing.”

When PEOPLE was given a special sneak peek at some of the outfits among around 75 on show at the palace (another 75 or so are in Holyroodhouse in Edinburgh and Windsor Castle, west of London), it became clear that it isn’t just the couture dressing that has been important to the Queen throughout her 64-year reign.

She uses color and special details to signify respect for a country she may be visiting – such as the green evening gown for her visit to Mexico in 1975, unveiled for PEOPLE exclusively, or the black Norman Hartnell design and delicate mantilla for a trip to the Vatican in 1961.

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“It’s an important aspect of the Queen’s wardrobe whereby a color or embroidery motif can convey messages without the need to speak. The clothes perform a diplomatic role,” de Guitaut notes.

For an exclusive look at the exhibit, pick up this week’s issue of PEOPLE

One of the exhibit’s biggest show-stoppers: a Hardy Amies design for a splendid night at the White House in 1957, when she and husband Prince Philip visited with then-President Dwight Eisenhower and First Lady Mamie.

“It is a beautiful dress,” says de Guitaut. “And interesting in terms of its shape and cut and very much of the period.”

“What distinguishes it as Hardy Amies’ work is this pared-down, elegant tailoring of the dress,” she says. “He has used a restrained degree of embroidery on the clothes. It is subtle.”

A major role in the Queen’s life over her long reign has been as head of the armed forces. Like her forebear Queen Victoria (whose record reign Elizabeth passed last year) she had a specially designed military-style tunic to wear when reviewing the troops. (The two outfits are displayed alongside each other in the exhibit.)

Designed by Bernard Weatherill for riding sidesaddle, de Guitaut says it was chosen to show how “British tailoring is right at the heart of British fashion. The Sovereign must be militarily correct and yet there is this feminizing input.”

The exhibit “was conceived for Her Majesty’s birthday and the idea for the theme was to really use fashion as the perfect barometer of the longevity of her life and the key highlights of her reign,” she adds.

That means featuring her wedding dress and the Sir Normal Hartnell-designed creation for her 1953 Coronation.

And there is the Angela Kelly outfit that she wore to the 2011 wedding of Prince William to the then- Kate Middleton.

Tickets ($28.50 for adults) for the summer exhibit that runs until October 2 are available from the Royal Collection website.