Dressing The Princess For Special Occasions
Dress designers often get their inspiration from foreign cultures. This was useful for Princess Diana when her wardrobe on royal engagements and overseas tours had to compliment her hosts and, at times, take their sensibilities into account.

Princess Diana introduced herself to the Japanese by wearing their flag
One clever choice of outfit, for example, was the white dress with large red dots which Diana wore during her tour of Japan in 1986. Diana could not have chosen anything more appropriate for her first day in Japan. In effect, she was introducing herself to the Japanese by wearing their flag, or at least a version of it. The large red dots echoed the emblem of the Rising Sun, the symbol of Japan, and the significance of this was not lost on the royal couple's hosts. They were highly pleased.
Another clever choice was a beautiful evening dress designed by Catherine Walker, which Diana wore during her visit to Thailand in 1988 for the celebrations of the King's 60th birthday. The evening dress combined two adventurous colours, purple and crimson, and was fully made of chiffon. Instead of a diamond tiara, Diana wore silk flowers in her hair to compliment with the dress, giving her a typical exotic look.
On her very first public appearances as Princess of Wales, Diana used her wardrobe to compliment her hosts. At the Braemar Games in Scotland in 1981, she joined in the Royal Family's tradition of wearing tartan. Shortly afterwards, on her first tour to Wales in November 1981, she wore a suit in the Welsh national colours of red and green with a matching wide-brimmed hat.
As time went on, wearing clothes that borrowed colours and other features from a host's culture or customs became a regular feature of Diana's wardrobe. Sometimes this was only subtly achieved, sometimes it was more straightforward. For instance, when Diana visited Sand Hurst Military Academy in 1987, she wore a white 'drum majorette' two-piece suit trimmed with rows of gold braid.

The loose-fitting white and lilac top and trousers that was worn by Diana were perfect for dinning cross-legged on cushions, as is customary in the Gulf States
In 1990, Diana visited the Royal Hampshire Regiment, of which she was Colonel-in-Chief. This time, she did not bother with adaptations. Instead, she had a copy specially made of the Royal Hampshire's mess jacket made by Gieves and Hawkes, the Saville Row tailors, and wore it with regulation white shirt, gold-buttoned white waistcoat and black bow tie.
On her choices of outfits for royal engagements and overseas tours, Diana said: "When I first arrived, there were a lot of people to help me. It's now really my choice."
In 1991, Diana went almost totally ethnic and complimented her Pakistani hosts, the Chitral Scouts, by wearing a soft white cap with jewels and feathers ornamenting the front, and a top intricately embroidered with gold interlinked diamond-shapes that were emphasized by crimson, green and blue lozenges.

Princess Diana, pictured visiting Al Azhar Mosque in Cairo in 1992, covered her head with a shawl as a mark of respect for Islamic traditions
However, choosing an outfit might be as challenging and tricky, especially when travelling to the Middle East, where female dresses have to be modest and unrevealing.
When touring the Gulf State with Charles in 1989, for example, Diana chose tight white trousers and a long lilac and white tunic. The loose-fitting top and trousers did not offend the sensibilities of her male hosts, and were perfect for desert picnics and for dinning cross-legged on cushions, as is customary in the Gulf States. It also helped the Princess cope with the intense heat of the desert climate and was much better choice than the long, heavy skirts worn by the Queen or other royal female members on their own visits to the Muslim countries.
In another occasion, at a dinner reception hosted by King Fahad in Riyadh, Diana wore a black and white gown that picked up the colours of the robes worn by the men around her. The gown was designed by The Emanuels, and with it, Diana wore Queen Mary's tiara given to her by the Queen on her marriage to Prince Charles.
Not all Muslim countries, of course, are quite as strictly traditional as this. Egypt, for instance, is much more westernized. When Diana stopped off there on her honeymoon in 1981, she was able to wear her short skirts.
Diana's outfit made diplomatic fashion statements, and were cleverly conceived to fit in with the rest of her wardrobe. The trick was not only to create something which her hosts could identify as a compliment, but also to further Diana's image as a smart and elegant princess.
Reference: Diana: An Extraordinary Life, a tribute magazine in 26 issues. Published in 1997.