The upcoming coronation of King Charles will mark the first time a male British royal has worn a crown at a coronation since Charles’ grandfather, King George VI, in 1937

Queen Elizabeth II and Prince Phillip wave from Buckingham Palace. PHOTO: UNIVERSAL HISTORY ARCHIVE/UIG VIA GETTY

He was her companion for 73 years, but Queen Elizabeth’s husband, Prince Philip, never wore a crown.

That’s because the late royal wasn’t a king — even though he was married to the woman who was the Queen of England for more than 70 years.

The title of “King” is only given to a male who inherits the throne and reigns as monarch.

Instead, Prince Philip — who was previously the Prince of Greece and Denmark — adopted the title of Duke of Edinburgh. After Queen Elizabeth took the throne when her father, King George VI, died in 1952, Prince Philip became known as “Prince Consort.” But since he was a prince, and not a king, Phillip wasn’t crowned as part of the coronation ceremony in 1953.

The rules are different, however, when the reigning monarch is male, as the world will see on May 6 at King Charles’ coronation.

The monarch will obviously be crowned at the ceremony at Westminster Abbey. And Charles’s wife of 18 years, now called Queen Camilla, will also be crowned, because she holds the title of “Queen Consort” — not “Princess Consort.”

King Charles and Queen Camilla. ANDREW MILLIGAN/GETTY

There was some speculation about what Camilla’s title would be, largely due to controversy over their affair during Prince Charles’s marriage to Princess Diana and Camilla’s marriage to her first husband, Andrew Parker Bowles. Camilla’s status as a divorced woman also played a role in her potential title.

“Queen Consort” is the traditional title for the wife of a reigning monarch. The title of “Queen” is reserved only for female rulers who became monarch through the line of succession.

On the day their 2005 engagement was announced, a press release stated: “It is intended that Mrs. Parker Bowles should use the title HRH The Princess Consort when The Prince of Wales accedes to The Throne.”

But that all changed in a message released marking the 70th anniversary of Queen Elizabeth’s reign. The monarch, then 95, announced, “when, in the fullness of time, my son Charles becomes King, I know you will give him and his wife Camilla the same support that you have given me; and it is my sincere wish that, when that time comes, Camilla will be known as Queen Consort as she continues her own loyal service.”

The coronation will mark the first time a male British royal has worn a crown since since Charles’ grandfather, King George VI, in 1937 — except, of course, when Charles was crowned as the Prince of Wales in 1969.

St Edwards Crown. TIM GRAHAM PHOTO LIBRARY/GETTY

And what crowns they are! The monarch will actually wear two crowns at the coronation: Charles will officially be crowned with the St. Edward’s Crown, which was crafted in 1661 with a solid-gold frame that’s adorned with semi-precious stones from tourmalines, topazes, rubies, sapphires, zircons and aquamarines.

He will then switch to the Imperial State Crown, which is worn by monarchs more frequently in public — such as at ceremonies like the State Opening of Parliament.

As for Queen Camilla, she will be crowned with the Queen Mary’s Crown. Set with 2,200 diamonds, it was last worn by Queen Mary — the late Queen Elizabeth’s grandmother — when she took part in the coronation alongside her husband, King George V, in 1911.

The crown will be slightly altered to include a special touch honoring Queen Elizabeth. Work is underway to reset the headpiece with the Cullinan III, IV and V diamonds — which are part of the famous Cullinan diamond, the largest ever found — that were part of the late monarch’s personal jewelry collection, which she often wore as brooches.

After the coronation, the crowns will be displayed in a new exhibit in the Jewel House at the Tower of London, opening May 26.