The Prince and Princess of Wales put on a united show with the Duke and Duchess of Sussex after they viewed tributes outside Windsor Castle.
ITV News' Royal Editor Chris Ship reports
The Prince and Princess of Wales have visited the gates of Windsor Castle to view the thousands of floral tributes left by members of the public in honour of the late Queen Elizabeth II.
In a surprise appearance, they were joined by Prince Harry, Duke of Sussex, and his wife Meghan Markle, the Duchess of Sussex.
There have been rumours of a rift between the two couples since Prince Harry made the controversial decision to break off from the Royal family and move to California.
However in his first speech as King yesterday, Charles III spoke of his love for the couple, "as they continue to build their lives overseas."
The Prince and Princess of Wales and Duke and Duchess of Sussex shook hands with hundreds of members of the public
The two couples viewed flowers and tributes outside the Castle gates and then made their way down the road outside, shaking hands and speaking to hundreds of members of the public who had gathered to see them.
Earlier in the day, William attended an Accession Council Ceremony where his father, King Charles III, was proclaimed monarch.
People who saw the couples at Windsor Castle said that seeing them together - for the first time since June - had made the day special.
"With everything going on it's nice that they all came out together," said one lady. "That was really special."
Another man, who was there with his wife and two children, said he "wasn't expecting to see Meghan."
"Family is everything," said another woman who had waited to catch sight of the Prince and Princess. "I'm sure if she's looking down - Ma'am - she'd be very, very happy."
Statement from the new Prince of Wales
In a statement released earlier, the new Prince of Wales said: "On Thursday, the world lost an extraordinary leader, whose commitment to the country, the Realms and the Commonwealth was absolute. So much will be said in the days ahead about the meaning of her historic reign.
"I, however, have lost a grandmother. And while I will grieve her loss, I also feel incredibly grateful. I have had the benefit of the Queen's wisdom and reassurance into my fifth decade."
He added his wife, the Princess of Wales, had had "twenty years of her guidance and support. My three children have got to spend holidays with her and create memories that will last their whole lives."
"She was by my side at my happiest moments. And she was by my side during the saddest days of my life.
"I knew this day would come, but it will be some time before the reality of life without Grannie will truly feel real.
Prince William earlier met with members of the public outside Windsor Castle with his wife, Prince Harry, and Meghan Markle
"I thank her for the kindness she showed my family and me. And I thank her on behalf of my generation for providing an example of service and dignity in public life that was from a different age, but always relevant to us all.
"My grandmother famously said that grief was the price we pay for love.
"All of the sadness we will feel in the coming weeks will be testament to the love we felt for our extraordinary Queen.
"I will honour her memory by supporting my father, The King, in every way I can."