A pair of wood shoe form made for Princess Diana, hangs on the wall at the Italian luxury shoemaker Tod's in Sant'Elpidio a Mare, April 17, 2014. REUTERS/Max Rossi

A journalist attends a preview of a new exhibition of dresses worn by the late Princess of Wales Diana, at Kensington Palace in London, Britain February 22, 2017. REUTERS/Peter Nicholls - RTSZUJO

The bodice of Princess Diana's Emanuel ball gown from the 1986 'Diaghilev' collection is seen at Kerry Taylor Auctions in London November 27, 2013. The dress is expected to earn 50-80,000 pounds (US$80-130,000) when it goes on auction December 3. REUTERS/Suzanne Plunkett

Journalists attend a preview of a new exhibition of dresses worn by the late Princess of Wales Diana, at Kensington Palace in London, Britain February 22, 2017. REUTERS/Peter Nicholls - RTSZUJX

Gold sequins, crystals and pearl beads are seen in this detail of Princess Diana's Emanuel ball gown from the 1986 'Diaghilev' collection at Kerry Taylor Auctions in London November 27, 2013. The dress is expected to earn 50-80,000 pounds (US$80-130,000) when it goes on auction December 3. REUTERS/Suzanne Plunkett

Journalists attend a preview of a new exhibition of dresses worn by the late Princess of Wales Diana, at Kensington Palace in London, Britain February 22, 2017. REUTERS/Peter Nicholls - RTSZUIU

Britain's Princess Diana holds Prince Harry during a morning picture session at Marivent Palace, where the Prince and Princess of Wales are holidaying as guests of King Juan Carlos and Queen Sofia, in Mallorca, Spain August 9, 1988. REUTERS/Hugh Peralta

Assistant Lucy Bishop displays detachable sleeve panels on Princess Diana's Emanuel ball gown from the 1986 'Diaghilev' collection at Kerry Taylor Auctions in London November 27, 2013. The dress is expected to earn 50-80,000 pounds (US$ 80-130,000) when it goes on auction December 3. REUTERS/Suzanne Plunkett

Princess Diana's dresses are seen at a preview of a new exhibition of outfits worn by the late Princess of Wales, at Kensington Palace in London, Britain February 22, 2017. REUTERS/Peter Nicholls - RTSZUJJ

Princess Diana arrives at the Royal Geographical Society in London for a speech on the dangers of landmines throughout the world June 12, 1997.

Journalists attend a preview of a new exhibition of dresses worn by the late Princess of Wales Diana, at Kensington Palace in London, Britain February 22, 2017. REUTERS/Peter Nicholls - RTSZUJM

A journalist attends a preview of a new exhibition of dresses worn by the late Princess of Wales Diana, at Kensington Palace in London, Britain February 22, 2017. REUTERS/Peter Nicholls - RTSZUJN