The touching reason Princess Diana hardly ever wore hats on visits with children

There is no doubt that royal fashion is carefully considered, with outfits curated for the occasion and seldom just thrown together.

This was certainly true of Princess Diana, who had a specific rule for events with children, and that was that she could never wear hats.

She said: “You can’t cuddle a kid in a hat," Kensington Palace curator Claudia Acott Williams has revealed.

The Royal Design in the Building exhibition, which opened at Kensington Palace on Thursday, June 3, features the sketch of a blue floral outfit regularly worn by the Princess of Wales when she visited children or hospitals. The floral piece, by creator David Sassoon, became referred to as her "caring outfit" because "she knew children loved the dazzling, floral pattern".

In the sketch, the model is wearing a hat, however the royal never paired a co-ordinating headpiece for events with children. Even so, Acott Williams offers that she did dress in "big outfit jewellery because she'd pick children up and they would take up with it".

"She understood how what you had been wearing could genuinely convey warmth... it might reinforce hierarchy or it could undermine hierarchy and produce more of a marriage," says Acott Williams.

"This brightly coloured floral was an extremely important piece in her working wardrobe."

Matthew Storey, curator at the Historic Royal Palaces, says that the case in point "really illustrates just how carefully she considered the people she would encounter when selecting outfits for her many public engagements."

Also included in the exhibition is Princess Diana's wedding dress, which is on public display for the very first time in more than 25 years.

The gown, which the past due Princess Diana wore to marry Prince Charles at London's St Paul's Cathedral on July 29, 1981, was designed by David and Elizabeth Emanuel. It'll be on screen at Kensington Palace, London, from Thursday until January 2.

It is on display with the princess's 7.6-metre sequin-encrusted train, which is the longest in Uk royal history to day.

To add the dress, and also other personal components of the past due royal, Historic Royal Palaces had to get authorization from her sons, Princes William and Harry.

Also included in the exhibition are the pink David Sassoon outfit and jacket that Princess Diana became later on her wedding day, together with artefacts detailing the creation of her bridal dress.

The exhibition features pieces worn by other British royals, like the surviving toile for the 1937 coronation costume of the Queen Mom and a Georgian-style dress worn by Princess Margaret, the sister of Queen Elizabeth II, to a 1964 charity costume ball.