'The Crown' Casts Elizabeth Debicki as Princess Diana in Seasons 5 and 6

The engagement ring of the century (yep, the same sapphire sparkler that Kate Middleton now totes around) made its debut when Prince Charles and Lady Diana Spencer announced their engagement on the grounds outside of Buckingham Palace.

Prince Charles and Diana pose with Queen Elizabeth II at Buckingham Palace after she gave her consent for their wedding. Is it just me or does everyone look rather...tense?

Diana and Charles are seen leaving St. Paul's Cathedral after their first wedding rehearsal on June 12, 1981—47 days before the big day. Hey, if you were getting married in front of, oh, I don't know, the entire world, you'd want lots of practice too.

Diana is seen leaving Emanuel's after the final fitting for her wedding dress a week before the big day. The suspense!

Husband and wife designers David and Elizabeth Emanuel were tapped to design Lady Di's dreamy taffeta gown. The designs were kept secret until the day of the ceremony, when the press was given a sketch of what they'd see on the steps of St. Paul's Cathedral.

This time, Diana and Charles leave the church only two days before their wedding. Appropriate.

Crowds camped out along the procession route the night before the wedding to ensure a good view.

A firework display took place over London on the eve of Charles and Diana's wedding on July 28, 1981.

On their wedding day, celebrations were seen throughout the United Kingdom. In Wales, the Royal Air Force performed a formation of the Prince of Wales Feathers over Caernarfon Castle.

Remember those campers? They lined the streets with British flags and decorations, hoping to get a glimpse at the couple upon their arrival.

They also relayed messages of support for the royal couple along the procession route. Seeing these signs HAD to calm Diana's nerves.

Press from every nation, including the United States, set up outposts to live broadcast the events. Here, Today hosts Willard Scott, Jane Pauley, and Tom Brokaw enjoy a spot of tea (as one does) before the ceremony.

Seriously, can you imagine driving past all of this before your wedding?

Two of the most stylish royals, Princess Anne and Princess Margaret, arrived first and did not disappoint. Those colors! Those coordinating fascinators! Just wow.

Princess Diana's bridesmaids were treated like royalty (granted, some of them were royalty), arriving in a gold carriage.

The day's festivities drew some of the most important royals from around the world—including Princess of Monaco Grace Kelly. How chic is she?!

First Lady Nancy Reagan wore a blush outfit to the nuptials. Unparalleled glamour, I tell you.

Prince Charles waves to the excited crowds along the processional—an appropriate response to the many people who camped out ahead of his wedding, if you ask me.

There are few moments more anticipated by the public than this one. Princess Diana arrived at St. Paul's Cathedral and everyone finally got to see her dress. How Diana managed to fit all that taffeta into one carriage? The world will never know.

When the bride stepped out of the carriage, she revealed a 25-foot-long train and veil. Absolutely breathtaking.

Prince Charles patiently waits for Diana to arrive while flanked by his two groomsmen, brothers Prince Andrew and Prince Edward.

Diana and her father make their way to the altar. Can you imagine how wild their nerves must have been at this moment??? P.S. Take a closer at the Spencer Tiara—yep, she wore her own family jewels for her big day.

The pews were packed with more than 3,500 guests. Shout out to Prime Minister Margaret Thatcher to Diana's right.

Honestly, how gorge is St. Paul's Cathedral? Obsessed.

Every bride wants to impress their mother-in-law, but when your MIL also happens to be the Queen, it's customary to give a curtsy upon seeing her—even at your own wedding.

Sarah Armstrong-Jones, a.k.a. Princess Margaret and the Earl of Snowdon's daughter, was the chief bridesmaid.

Princess Diana had a total of five bridesmaids: Clementine Hambro, Catherine Cameron, Sarah-Jane Gaselee, India Hicks, and Lady Sarah Armstrong-Jones. Sarah was even trusted with holding Diana's bouquet!

Diana let her nerves show when she accidentally mixed up Prince Charles' full name, referring to him as Philip Charles Arthur George rather than Charles Philip Arthur George. (I mean, who can blame her, that name is a mouthful.)

The couple share a private moment during the ceremony. What do you think they were talking about? How much they wanted a glass of bubbly?

The couple looked b-e-y-o-n-d regal as they made their way down the aisle after saying "I do."

Sure, you've seen this shot, but have you ever noticed the mountains of flowers displayed at the entrance of church? Didn't think so.

As is traditional, the Queen lead the charge for departing guests.

Charles and Diana were greeted by more than 60,000 well-wishers as they made their way from St. Paul's Cathedral to Buckingham Palace.

The couple's carriage drove along Fleet Street on their way to Buckingham Palace.

Police were out in full force to manage the massive crowds along the procession route. Wouldn't you fight your way through to catch a glimpse at the newlyweds?

Prince Charles and Princess Diana's signatures, along with those of their family as witnesses, make it official official.

The couple had their reception at Charles' home, which just so happens to be, ya know, Buckingham Palace. The Queen was one of the first to arrive.

The newlyweds also arrived at the private entrance of Buckingham Palace for their reception, wedding party in tow.

A very important task.

The Queen and her new daughter-in-law share a laugh while on the balcony of Buckingham Palace.

Charles and Diana appear rather bashful on the balcony, where it's customary to share a kiss. TBH, a pretty normal reaction, considering the enormous crowds that were watching.

The couple eventually gave the people what they wanted!

Remember cramming into your high school club photo? This was a lot like that, except instead of a bunch of ultimate frisbee kids, it's a giant group of all of Europe's royal families. Casual.

When you have to feed thousands of guests at your reception, one cake will not do—so they had 27. But their official cake was a multi-tiered fruit cake made by the head baker at the Royal Naval Cookery School.

Keeping up with tradition, Diana's bouquet was laid upon the tomb of the Unknown Warrior Grave in Westminster Abbey. The Princess' bouquet, made up of white orchids, freesias, gardenias, and lily of the valley flowers, weighed around 2 kilos (that's over 4 lbs!) and was nearly 42 inches long.

After the wedding of the century, Charles and Diana made their way through the crowds once more, this time to embark on their honeymoon.

The newlywed's carriage was decorated with a "Just Married" sign, as well as mylar balloons with the Prince of Wales feather on them.

In a glamorous exit, the couple departed from Waterloo Station by train. They spent their first three nights as a married couple in the Broadlands, the same place Prince Philip and Queen Elizabeth spent their wedding night.

Where does a royal couple honeymoon, you ask? On the royal yacht, of course. After the Broadlands, Charles and Diana set sail from Gibraltar to travel around the Mediterranean.

The couple arrived in Scotland for the final leg of their honeymoon, looking quite ~sun-kissed~.

The couple welcomed photographers to Balmoral, the Queen's estate in Scotland, for a photo call at the end of their trip, officially closing out the royal wedding extravaganza.

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