In the wake of the Queen's death on Thursday, Prince William and Kate - who are now known as Prince and Princess of Wales - made an appearance in Winsdor and they surprisingly reunited with Prince Harry and Meghan Markle for the emotional outing.
READ: Princess of Wales reveals Prince Louis' first words after being told about Queen's death
Harry and Meghan joined the pair after the Prince of Wales personally extended an invitation to them.
MORE: When will the Queen's cause of death be revealed?
They greeted royal fans as they congregated to mourn the loss of the 96-year-old monarch who died "peacefully" in Balmoral.
WATCH: Prince and Princess of Wales and the Duke and Duchess of Sussex unite at Windsor for emotional walkabout
Dressed in black, the royals looked sombre as they stopped to shake the hands of teary fans who were standing behind a barrier. They were surrounded by police protection as they made their way around the crowds.
© Photo: Getty ImagesThe Prince of Wales invited his brother and Meghan to the walkabout
STORY: Why Balmoral was a poignant location for the Queen's death
READ: Why Prince Charles and Princess Anne were first at Queen's bedside at Balmoral
Both of the royal ladies opted for smart black dresses, while Princes William and Harry donned black suits.
© Photo: RexThe royals arrived together
William and Harry hadn't been seen together at Windsor since the funeral of their grandfather, Prince Philip. Although both had been present at during the Queen's Platinum Jubilee celebrations they were not fully together.
© Photo: RexTouching tributes had been left for the Queen
Crowds broke into applause seeing the royals couples together with William, Kate and Meghan shaking hands with members of the public. The Princess of Wales approached a crying child who stopped when she grew nearer.
© Photo: Getty ImagesHarry consoled his wife
Meghan approached a stunned teenager and put her hand on her shoulder as a sign of reassurance. The girl then asked the Duchess for a hug, which Meghan gave to her.
© Photo: Getty ImagesBefore the walkabout, the royals read tributes left for the Queen
At one point William was handed a miniature Paddington Bear toy, after the late monarch captured the hearts of the public during a skit with the famous character during her Jubilee celebrations.
© Photo: Getty ImagesThe Princess of Wales was touched by wellwishers' words and flowers
One person was seen waving a Welsh flag, referencing the new titles of William and Kate.
© Photo: Getty ImagesThe Princess also hugged members of the public
The royal pairs walked separately from one another, both speaking to people on opposite sides of the road.
© Photo: Getty ImagesThousands lined up to greet the royals
William joked with members of the public but was also seen casting a more sombre tone as he spoke about his late grandmother with others.
© Photo: Getty ImagesKate opened up about her son Louis' reaction to the Queen's death
They arrived and left in the same car, after spending 40 minutes with the public, where they were handed flowers, balloons and other gifts.
© Photo: Getty ImagesMeghan and Harry will be staying in the UK until the Queen's funeral
Their surprise outing comes after Queen Elizabeth II died aged 96, surrounded by members of her immediate family. Deeply saddened by the news, Kate and William released a statement on their social media accounts.
© Photo: Getty ImagesMany were overcome with emotion after meeting the Duchess
Taking to Instagram, the duo penned: "The Queen died peacefully at Balmoral this afternoon. The King and The Queen Consort will remain at Balmoral this evening and will return to London tomorrow."
© Photo: Getty ImagesThe couple are staying at Frogmore Cottage
Prince William and Kate's Twitter account @KensingtonRoyal now refers to the couple as The Duke and Duchess of Cornwall and Cambridge.
Elizabeth II, 96, was the nation's longest-reigning monarch, serving as head of state for more than 70 years. The Prince of Wales is now King, having acceded to the throne immediately on the death of his mother.
© Photo: Getty ImagesThe couples left the outing together
Following the death of Her Majesty The Queen, it is His Majesty The King's wish that a period of Royal Mourning be observed from now until seven days after The Queen’s Funeral.
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