The Princess Royal married her first husband Mark Phillips at Westminster Abbey on November 14 of that year. The ceremony attracted around 500 million TV viewers from around the world, who saw Anne accompanied down the aisle by her late father, the Duke of Edinburgh. On her head, the Queen's daughter wore a stunning headpiece, known as the The Queen Mary's Russian Fringe tiara.

       The tiara is unique not only for its beauty, but also because it can be transformed into a necklace.

       A description on The Royal Collection Trust website states: "A diamond fringe tiara in the style of a Russian headdress or kokoshnik; it can also be worn as a necklace."

       Commissioned in 1919 by Queen Mary, it was originally a fringe necklace, as a wedding day gift from Queen Victoria.

       Mary was known for her love of refashioning her jewellery items into something new and more to her tastes.

       So 26 years after her wedding in 1893, she approached the jewellers Garrard with an unusual request.

       George V's wife wanted the company to turn the necklace into a kokoshnik-style piece, consisting of 47 graduated brilliant and rose-set tapering bars, separated by 46 narrower spikes.

       READ MORE: Princess Anne 'gets hands dirty' during unusual royal engagement

       The design had to be such that the tiara could still be turned back into a necklace.

       A kokoshnik is a traditional Russian headers worn by women and girls to accompany the sarafan - a long, trapezoidal Russian jumper dress.

       The kokoshnik tiara style was very popular in the 18th and 19th centuries, particularly with the Romanov imperial family.

       The Queen also wore the tiara when she married Prince Philip in 1947, as did Princess Beatrice at her wedding to Edoardo Mapelli Mozzi in 2020.

       DON'T MISS

       Princess Anne an 'unsung hero' amid Queen's grief, says Karren Brady [Reveal]

       'So much significance': Princess Anne given two engagement rings [Spotlight]

       'Ultimate pro' Princess Anne wows in Northern Ireland [Insight]

       Princess Anne wore a wedding dress designed by Maureen Baker, which featured a Tudor-style cut with a high collar and medieval sleeves.

       She arrived at the Abbey in a horse-drawn carriage, accompanied by her late father.

       The Princess Royal announced her separation from Mark Phillips in August 1989, before divorcing in 1992.