Today is the official celebration of Queen Elizabeth II's birthday, and it's a party she has diligently attended throughout her 70-year reign.
Trooping the Colour is the sovereign's personal inspection of British and Commonwealth regiments.
But the moment everyone will be waiting for is the balcony appearance at Buckingham Palace at the end.
After two turbulent years, who shows up — and who doesn't — will offer a rare glimpse into the monarchy's state of affairs.
What is Trooping the Colour?
Trooping the Colour is a ceremony that can be literally translated to "carrying the flag".
To know who was who on the battlefield, soldiers needed to be able to recognise each regiment's colour — a military term for flag.
As a military exercise, guards would troop, or carry, the colour down the ranks so everyone could get a look.
It was first used to mark the sovereign's birthday in 1748 during the reign of King George II and became an annual event after the accession of King George III in 1760.
Since then, Trooping the Colour has become a display of pomp and pageantry that is watched by millions of people.
Queen Elizabeth II has attended the event every year of her reign, except in 1955 when it was cancelled due to a national rail strike.
As Colonel of the Grenadier Guards, Princess Elizabeth became the first woman since Queen Victoria to ride in the ceremony in 1947.
She rode a horse in the annual parade until 1987, when she started to use a carriage.
A significantly pared-back Trooping the Colour was held at Windsor Castle in 2020 and 2021 due to the COVID-19 pandemic.
What happens in Trooping the Colour?
Trooping of the Colour starts at Buckingham Palace in London.
Members of the royal family are driven in carriages down The Mall to the Horse Guards Parade.
The Queen is the last to leave, in her own carriage, and is escorted by the Household Cavalry Mounted Regiment.
When she arrives at the Parade, she is greeted by a Royal Salute and inspects the troops.
This year, the 1st Battalion Irish Guards will troop their colour.
The Queen then returns to the palace, where she is joined on the balcony by members of the royal family to watch a fly-past by the Royal Air Force.
Who will appear on the balcony?
A lot has changed since the last happy family snap taken at Trooping of the Colour in 2019.
At the time, the Queen appeared on the balcony with 41 royal relatives.
Notably absent was her husband Prince Philip, who had not appeared since he retired from public duties in 2017.
Instead, the Queen was flanked by her two eldest sons Prince Charles, heir to the throne, and Prince Andrew.
Nearby were Prince Harry and wife Meghan.
In January 2020, Harry and Meghan effectively quit as "senior royals" and later moved to North America.
Their scathing interview with Oprah in March 2021 alleged members of the royal family and palace aides bullied Meghan and were concerned about how dark their son Archie's skin might be.
When Harry returned to the UK in April 2021 for Prince Philip's funeral, he appeared relatively friendly with his brother Prince William despite reports their relationship was fractured.
Both Meghan and Harry are due to return to the UK with their young children Archie and Lillibet for the Jubilee celebrations.
However, they will not appear on the balcony, which will be limited to "working royals".
This is partly due to Prince Charles's wish to cut down on excess royals, but also to remove the family's biggest problem — Prince Andrew.
Prince Andrew was stripped of military affiliations and royal patronages in January as he faced a civil sexual assault case in the United States.
The case was dismissed in February after he reached a settlement with Virginia Giuffre, who alleged she was sexually abused when she was underage.
The settlement included an undisclosed payment, with Prince Andrew making a "substantial donation" to Ms Giuffre's charity in support of victims' rights.
The prince did not admit wrongdoing in agreeing to settle the civil lawsuit. He had not been accused of criminal wrongdoing.
The Sun, a British tabloid, reported Prince Charles bankrolled most of the settlement, with the Queen chipping in.
Prince Andrew's first public appearance after the settlement was escorting his mother to the memorial for Prince Philip in March.
It was reported senior royals were "dismayed" by Prince Andrew's public involvement on the day, but it will remain to be seen if he plays a significant role in the Jubilee celebrations.
His role as Colonel of the Grenadier Guards, which he took over from his father in 2017, was returned to the Queen this year.
Prince William, as Colonel of the Irish Guards, oversaw the responsibility of taking part in the Trooping the Colour dress rehearsal on Saturday.
When is Trooping the Colour?
This year, Trooping the Colour is back in London to kick off the Queen's Platinum Jubilee.
You can watch it in Australia live on free-to-air TV on Channel 7 from 8:30pm AEST on Thursday, June 2.
Queen Elizabeth II is the first British monarch to mark 70 years of service.
When is the Queen's birthday public holiday?
The Queen's birthday and Platinum Jubilee are being celebrated in the United Kingdom with a special public holiday weekend.
Australians won't get any extra public holidays to mark the occasion.
Most states and territories (NSW, Vic, SA, Tas, ACT, NT) get the Queen's Birthday public holiday on Monday, June 13.
WA has it on Monday, September 26, but some regional areas have a different date.
Queensland has it on Monday, October 3.
The Queen's actual birthday is April 21.
