Meghan, Duchess of Sussex, smiles with Prince Harry. Photo / Getty Images
There are some invitations you cannot refuse, particularly when it is your grandmother-in-law's birthday party, and she is the Queen.
Meghan, the Duchess of Sussex, came back from maternity leave after the birth of son Archie on May 6 to celebrate all the pomp and ceremony of the Trooping of the Colour with Her Majesty in London, reports news.com.au.
More than 1400 soldiers, who had trained for months, 300 horses and 400 musicians, were on display to honour the Queen.
The Queen arrived in a procession full of pageantry featuring a Sovereign's Escort from the Household Cavalry, made up of Life Guards and Blues and Royals, in their silver and gold breastplates and plumed helmets.
Prince Charles, the Colonel of the Welsh Guards, and Prince William, Colonel of the Irish Guards, donned their uniforms and arrived on horseback for the parade.
Prince Harry joined Meghan, Kate, the Duchess of Cambridge, and Camilla, the Duchess of Cornwall in a carriage down The Mall to cheers from thousands of royal fans.
The Queen's invitation to Meghan trumped that of the United States president earlier in the week.
Meghan was a notable absentee at a state banquet for Donald Trump at Buckingham Palace, who had denied he had called her "nasty" in relation to comments she made about him before the 2016 US election.
The royal treatment was laid on for the Queen for the ceremony, which has marked the British sovereign's birthday for the past 260 years.
The celebration was the official birthday party, but the Queen's actual birthday is on April 21, where she turned 93 this year.
As sharp as ever, she watched as the soldiers marched in front of her for the traditional parade supported by the marching bands.
The Queen wore an Angela Kelly tweed dress in shades of pale pink, mint yellow and gold and a matching hat by Ms Kelly.
The monarch also wore a badge of the Brigade of Guards.
Meghan wore a navy dress by Clare Waight Keller and hat by Noel Stewart while Kate wore a favourite designer — an Alexander McQueen lemon-coloured dress and hat by Philip Treacy.
They were sitting opposite each other in the carriage, amid rumours of a rift between them across the UK press.
Camilla had also chosen a mainstay designer Bruce Oldfield who had created a bright green dress and coat with white embroidery teamed with a Philip Treacy hat.
The colour, or ceremonial regimental flag, being paraded this year was from the 1st Battalion Grenadier Guards, a front line infantry regiment of the British Army when not performing ceremonial duties.
Their lineage can be traced back to 1656 when the military unit was raised as the sovereign's bodyguards by King Charles II while in exile in Bruges.
The celebrations were expected to end with a Royal Air Force flyover of Buckingham Palace.
Most members of the royal family come together on the balcony of the palace to watch this every year.
Prince Louis and Princess Charlotte were spotted peering from a window at the palace before the fly over of aircraft. It is his first appearance at the event.
Prince Louis stole the show at the Queen's Trooping of the Colour celebrations.
Kate and William took turns in holding their 13-month old son in her arms as the royal family watched the traditional Royal Air Force flyover on the balcony of Buckingham Palace.
Louis' enthusiastic clapping after the end of the national anthem melted hearts.
With his older brother and sister, Prince George and Princess Charlotte, stood nearby with William he waved at the crowds enthusiastically and carried on waving as his father carried him inside.
Louis, who only last month was shown in pictures walking for the first time, appears to be a natural as he lapped up the applause from thousands of royal fans outside the palace gates.
Prince Philip, the Duke of Edinburgh, who celebrates his 98th birthday on Monday, has retired from official public duties and did not attend.