LONDON -- When Britain's 21-year-old Princess Elizabeth married 26-year-old Lieutenant Philip Mountbatten at Westminster Abbey in 1947, the wedding sparked joy and celebration in a country just recovering from World War II.

Seven decades on, the couple who would become Queen Elizabeth II and Prince Philip -- now 91 and 96, respectively -- are still going strong, their marriage a bedrock in British public life amid a world of change.

Britain's Queen Elizabeth II and Prince Philip, Duke of Edinburgh, seen in the White Drawing Room at Windsor Castle, in a photo released in celebration of their platinum wedding anniversary on Nov. 20. Matt Holyoak/CameraPress

On Monday, they mark their 70th wedding anniversary, though officials say the milestone will be celebrated privately and no public events are planned. The royal family is reportedly marking the date with a gathering at Windsor Castle.

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Ahead of the celebration, new photos were released showing Queen Elizabeth II and Prince Philip.

BBC News reports that the images are part of a series by celebrity photographer Matt Holyoak, whose first portrait of them was revealed over the weekend.

The Queen wears a cream dress from her dressmaker of the last 15 years Angela Kelly. A golden "Scarab" brooch was a gift to the Queen from Prince Philip in 1966.

The queen is the first monarch in British history to celebrate a platinum wedding anniversary.

At their 50th wedding anniversary, Elizabeth praised her husband as "quite simply ... my strength and stay all these years."

Elizabeth first met Philip, a naval officer and the son of Prince Andrew of Greece, as they attended the wedding of Philip's cousin in 1934.

The pair wed at Westminster Abbey in London on Nov. 20, 1947.

At the time, Winston Churchill summed up the occasion in 1947 as "a flash of colour on the hard road we travel," according to BBC News.

It would be nearly another six years before Elizabeth would be crowned as monarch, also at Westminster Abbey.

In the decades that followed, Philip, who also holds the title Duke of Edinburgh, spent almost the entire duration of their marriage supporting his wife in her role as head of state. Both have cut back on their public engagements in recent years, and Philip retired from official duties earlier this year.

The royal couple has four children, eight grandchildren and five great-grandchildren.

BBC News adds that the Royal Mail has issued a set of six commemorative stamps for the occasion that feature the couple's engagement and wedding.