The Duke and Duchess arriving at Buckingham Palace this morning.
The Duchess travelled in the procession with Camilla, Harry and Meghan.
Trooping the Colour is an annual highlight on the summer calendar - promising a stunning display of pomp and pageantry in London.
Another view of the carriage procession.
There's lovely footage of the duchesses in the video below.
Another view from the Army in London.
The Yorks travelled in the second carriage.
And the Wessexes in the third carriage.
Her Majesty travels down the mall.
Although the Queen's birthday is 21 April, it has long been tradition to celebrate the sovereign's birthday publicly on a day in June, when good weather is more likely. Her Majesty has attended Trooping the Colour every year since 1947 - except in 1955 when a national rail strike cancelled the event.
The background of the prestigious annual event? Trooping the Colour actually originated in traditional preparations for battle. Colours, or flags, were trooped down the rank so they could be seen by the soldiers. In 1748, it was announced the parade would also mark the sovereign's official birthday.
More on the history of the day:
'The Sovereign's birthday is officially celebrated by the ceremony of Trooping the Colour (Queen's Birthday Parade). This impressive display of pageantry takes place on a Saturday in June by her personal troops, the Household Division, on Horse Guards Parade, with Her Majesty the Queen herself attending and taking the salute. The parade route extends from Buckingham Palace along The Mall to Horse Guards Parade, Whitehall and back again.
During the ceremony, The Queen is greeted by a Royal salute and carries out an inspection of the troops. After the massed bands have performed a musical 'troop', the escorted Regimental Colour is carried down the ranks.The Foot Guards and the Household Cavalry then march past Her Majesty, and The King's Troop, Royal Horse Artillery, rank past.The Queen rides in a carriage back to Buckingham Palace at the head of her Guards, before taking the salute at the Palace from a dais.'
An enormous amount of planning and preparation goes into ensuring the annual event runs as smoothly as possibly.
Over 1,400 officers and military personnel are on parade, together with two hundred horses; over four hundred musicians from ten bands and corps of drums march and play as one. Some 113 words of command are given by the Officer in Command of the Parade. The parade route extends from Buckingham Palace along the Mall to Horse Guards Parade, Whitehall and back again.
The Colour of the 1st Batallion Grenadier Guards was trooped.
On horseback, Prince Charles, Colonel of the Welsh Guards; Prince William, Colonel of the Irish Guards; the Princess Royal, Colonel of the Blues and Royals; and Prince Andrew. Harry doesn't ride on horseback at the event as he's not a Royal Colonel yet, and nor did Andrew until last year when he succeeded his father as Colonel of the Grenadier Guards.
These three little cuties were spotted sneaking a peek.
This little man has the royal wave perfected already...
The family gathered on the balcony of Buckingham Palace at 1 pm.
Those Cambridge expressions :)
Louis looked impressed by the view.
A great shot of Kate and Charlotte.
The event culminates with a stunning show by the Royal Air Force. More than twenty-five military aircraft soar over Buckingham Palace in formations thirty seconds apart. Aerobatic team, the Red Arrows, decorate the skyline with red, white and blue smoke.
Louis makes a beeline for Dad.
Kate and her mini-me :)
When it came to choosing an outfit for Louis' debut, Kate dug into the archives for an adorable blue and white outfit Uncle Harry wore as a tot for the same event.
An overview from the balcony.
The Duchess wore a fabulous bespoke Alexander McQueen warm lemon dress for the event. The garment is beautifully designed and tailored, featuring a v neck, defined shoulders and peplum detail. It's a very fresh offering from Sarah Burton, and easily one of my favourite Trooping looks. The colour works wonderfully for Kate.
Kate teamed the piece with the Philip Treacy hat she wore for Harry and Meghan's wedding in May 2018.
The floral design is from the milliner's SS18 Collection.
Kate accessorised with the Queen's Bahrain pearl earrings. Kate has worn the earrings on several occasions including Royal Ascot in 2017. In 1947, the then Princess Elizabeth received seven larger pearls from the ruler of Bahrain, and two of the pearls were used to create the beautiful pair of earrings. From Her Majesty's Jewel Vault reports: "The earrings each contain one large round diamond and four smaller ones, three baguette diamonds, and a Bahrain pearl dangling below. The Queen seems to have worn them mainly in the early years of her reign; they were later unearthed for the Buckingham Palace summer exhibit marking her 60th wedding anniversary." More recently they were loaned to the Countess of Wessex.
And her diamond cross pendant.
A closer look at Kate's updo.
View the event in its entirety below.
We'll see William and Kate on Tuesday for engagements in Cumbria.