Prince William and Kate, Prince Harry and Meghan greet sea of mourners at Windsor

Princes William and Harry reunite to mourn Queen Elizabeth II

Many of the high-profile members of the royal family were seen visiting memorials to Queen Elizabeth II across the U.K. on Saturday. For most, it was the first time they were out in public since the queen died on Thursday.

(L-R) Catherine, Princess of Wales, Prince William, Prince of Wales, Prince Harry, Duke of Sussex, and Meghan, Duchess of Sussex, on the long Walk at Windsor Castle on Sept. 10, 2022, before meeting well-wishers. CHRIS JACKSON/POOL/AFP via Getty Images

Prince Harry and his wife, Meghan, the Duchess of Sussex, joined Prince William and his wife Kate, the Princess of Wales, at Windsor Castle to view the sea of floral tributes left by the public in honor of the princes' grandmother. The princes and their wives were seen shaking hands and speaking with members of the public.

Princess Catherine and Prince William greet people outside of Windsor Castle on Sept. 10, 2022. CBS News

Meghan, Duchess of Sussex, and Prince Harry, Duke of Sussex, greet mourners outside of Windsor Castle on Sept. 10, 2022. CBS News

(L-R) Meghan, Duchess of Sussex, Prince Harry, Duke of Sussex, Prince William, Prince of Wales, and Catherine, Princess of Wales, look at floral tributes laid by members of the public on the Long walk at Windsor Castle on Sept. 10, 2022, before meeting well-wishers. CHRIS JACKSON/POOL/AFP via Getty Images

People gather outside of Windsor Castle, west of London, on Sept. 10, 2022, two days after Queen Elizabeth II died at the age of 96. ADRIAN DENNIS/AFP via Getty Images

It was the two couples' first public appearance since the queen's death.

From L, Vice Admiral Timothy Laurence, Prince Andrew, Duke of York, Princess Anne, Princess Royal, Prince Edward, Earl of Wessex, Zara Phillips, Lady Louise Windsor, Britain's Sophie, Countess of Wessex, Princess Beatrice of York and Princess Eugenie of York greet members of the public gathered outside of Balmoral Castle in Ballater on Sept. 10, 2022, two days after Queen Elizabeth II died at the age of 96. OWEN HUMPHREYS/AFP via Getty Images

Elsewhere, Queen Elizabeth II's three youngest children — Princess Anne, Prince Andrew and Prince Edward — as well as their families greeted a crowd of people who gathered Saturday to line the route outside Balmoral Castle in Scotland, where the queen died two days earlier. They also took in the sea of floral tributes left by the public outside of the castle's gates.

Anne, Princess Royal, and Zara Tindall greet the public outside the gates of Balmoral Castle on Sept. 10, 2022, in Aberdeenshire, Scotland. Karwai Tang

Princess Eugenie, Andrew's daughter, was seen laying a bunch of flowers, while her sister, Princess Beatrice, and the rest of the family took time to read the many tributes to the queen.

Princess Eugenie and Princess Beatrice, who was recently appointed counsellor of state for King Charles III, look at flowers left by the public outside the gates of Balmoral Castle on Sept. 10, 2022, in Aberdeenshire, Scotland. Karwai Tang/WireImage via Getty Images

Prince Andrew, Duke of York looks at flowers left outside the gates of Balmoral Castle on Sept. 10, 2022, in Aberdeenshire, Scotland. Karwai Tang/WireImage via Getty Images

Princess Beatrice and Sophie, Countess of Wessex look at flowers left by the public outside the gates of Balmoral Castle on Sept. 10, 2022, in Aberdeenshire, Scotland. Karwai Tang/WireImage via Getty Images

Lady Louise Windsor, Sophie, Countess of Wessex, Prince Andrew, Duke of York, Prince Edward, Earl of Wessex, Anne, Princess Royal, and Timothy Laurence wave to the public outside the gates of Balmoral Castle on Sept. 10, 2022, in Aberdeenshire, Scotland. Karwai Tang/WireImage via Getty Images

Hours earlier, Prince William and Prince Harry's father, King Charles III, was officially proclaimed monarch of the U.K. during a ceremony in London. William, who is next in line to the throne, was also present at the ceremony.

King Charles III pledges "lifelong service" in 1st address

Since the queen's death, William and Kate have received new titles — they are now the Duke and Duchess of Cambridge and Cornwall, as well as the Prince and Princess of Wales. Harry and Meghan's titles have not changed, but their children are now Prince Archie and Princess Lillibet.