The following morning, on 30 May 1973, the couple stepped out on the grounds of Buckingham Palace to debut the bride-to-be's glittering sapphire and diamond engagement ring.
A flashback to the memorable royal moment, which occurred more than five decades ago, proves that Princess Anne's penchant for fashion was just as evident in her twenties as it is today.
In light of the anniversary of the Princess Royal's first engagement, HELLO! revisits Princess Anne's unmatched engagement style.
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Princess Anne's candy pink engagement dress
The then 23-year-old daughter of Queen Elizabeth II wore a candy pink blazer and pleated skirt to officially mark her engagement.
The striking suit, which featured peachy-toned tartan detailing amongst the skirt's pleats, along with a matching tartan neck-tie, highlighted the royal's feminine silhouette.
Princess Anne paired her cropped jacket and rule-bending knee-grazing skirt with a smart black handbag and patent leather court shoes - twinning with her mother who wore the same accessories in the official photographs.
The photograph was captured before the Princess Royal had adopted her signature chignon hairstyle that she has worn religiously for the last four decades.
Instead, Anne wore her brunette hair in a voluminous beehive, fastened with a French barrette that left her curled locks to fall past her shoulders.
At the time, an official statement was released by Buckingham Palace: "It is with the greatest pleasure that the Queen and Duke of Edinburgh announce the betrothal of their beloved daughter the Princess Anne to Lieutenant Mark Phillips, the Queen’s Dragoon Guards, son of Mr. and Mrs. Peter Phillips."
Princess Anne's trailblazing marriage history
Princess Anne, the Queen's second child and only daughter, and Mark tied the knot in November 1973. They went on to welcome son Peter in 1977 and daughter Zara in 1981 before they sadly announced their separation in August 1989.
This was the first time a child of the British monarch had remarried after divorce and defied the Church of England since the 2002 law had not yet come to fruition. Anne sidestepped this by marrying Timothy in Scotland.
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