Sharjah24 – AFP: Princess Diana's wedding dress for her 1981 marriage to Prince Charles was one of the best-kept secrets in fashion history.

The gown sparked such intense interest that young designers David and Elizabeth Emanuel locked the ivory silk dress, which had a 25-foot (7.6-metre) long train, in a safe at night.

Plucked from obscurity for the commission of a lifetime, the pair even took to putting dummy bits of fabric in the studio's bins to throw anyone rummaging through them off the scent, according to an exhibition of royal fashion, including Diana’s iconic dress, that opens on Thursday.

The exhibition -- Royal Style in the Making -– at the Orangery at Kensington Palace, Diana's home until her death in a car crash in Paris in 1997, focuses on the work of designers who dressed not just Diana but also Queen Elizabeth II, Princess Margaret and the Queen Mother.

Trimmed with vintage lace, pearls and thousands of sequins, the train of Diana's dress was the longest ever for a British royal bride and memorably appeared crumpled as she emerged from her carriage at St Paul's Cathedral.

Luckily, the designers were on hand to smooth it out.

The exhibition, which runs until January 2, chronicles some of the hard toil behind the dress, featuring photographs of the seamstresses as well as the keys for the safe where it was safely deposited nightly. 

The exhibition also highlights Diana's growing sense of personal style and evolution from girlish frills to sleeker, more impactful outfits. 

Her sons Princes William and Harry loaned both Diana's wedding and going-away dresses to the exhibition.

The most overtly sexy dress at the exhibition belonged to Princess Margaret and was made for a costume ball in 1964 by theatrical designer Oliver Messel.

With its low-cut, gold brocade-trimmed bodice, the dress was based on Georgian era fashion.