LONDON: Charles III was officially proclaimed king at a pomp-filled ceremony on Saturday as the grieving royal family revealed the detailed plans for the grand state funeral of Queen Elizabeth II.
As palace officials confirmed the September 19 date for an event expected to be watched by millions worldwide and attended by foreign leaders, Prince William broke his silence with an emotional tribute to his beloved "Grannie".
And in a surprise display of unity despite their recent rift, a black-clad William and his wife Kate emerged from Windsor Castle alongside Prince Harry and his wife Meghan to inspect flowers left by well-wishers.
"She was by my side at my happiest moments. And she was by my side during the saddest days of my life," said the 40-year-old William, who has now assumed the title of Prince of Wales.
"I knew this day would come, but it will be some time before the reality of life without Grannie will truly feel real."
William said he would "honour her memory by supporting my father, the king, in every way I can."
Trumpeters played and a court official wearing a feathered bicorn hat had earlier declared the 73-year-old Charles "our only lawful and rightful" monarch from the balcony of St James's Palace after a historic Accession Council meeting of senior royals, clergy and government.
The centuries-old tradition of the Accession Council was televised live for the first time as it officially announced Charles as monarch after seven decades as heir apparent.
"I am deeply aware of this great inheritance and of the duties and heavy responsibilities of sovereignty, which have now passed to me," Charles said in a speech before swearing an oath.
"In taking up these responsibilities, I shall strive to follow the inspiring example I have been set."
Eight trumpeters accompanied the proclamation that was followed by a rousing three cheers for the new king by red-jacketed Coldstream Guards soldiers, doffing their distinctive bearskin hats.
Ceremonial gun salutes had earlier boomed simultaneously across the United Kingdom and the proclamation -- a relic from the past where the new monarch needed to be announced to their subjects -- was also read publicly in Scotland, Northern Ireland and Wales.
Charles automatically became monarch upon the queen's death aged 96, but the proclamation is the latest step in the set piece 10-day programme building up to her state funeral.
The new king had made clear in a televised address the night before his pride in William, whose wife Kate assumes the title of Princess of Wales, once held by her husband's late mother, Charles' ex-wife Diana.
Charles also expressed his love for his younger son Harry and daughter-in-law Meghan, who stepped back from royal duties in 2020 and moved to North America.

But in an unannounced move, the two brothers emerged with their wives to speak to well-wishers outside Windsor Castle outside London.
The younger generation of royals shook hands with the crowd, although they remained on opposite sides of the road.
Crowds have also massed outside Buckingham Palace both to mourn the queen and to wish Charles well, greeting him with cheers and even kisses when he arrived from Scotland on Friday.
"I'm sad, but you have to move on. I think the king will be different," said 53-year-old Londoner Sarah Berdien as Charles was formally proclaimed nearby.
"The queen has always been the queen -- always the same, no drama."
Recruitment worker Dany Van Laanen, 36, said Charles has "big shoes to fill" as he replaces his widely venerated mother, who was the only monarch that most in the UK had ever known.
"I do hope he will manage to modernise the monarchy," he said.
Charles -- who has seen his popularity recover in recent years from the time of Diana's death in a 1997 car crash -- takes the throne at a moment of deep anxiety in Britain over the spiralling cost of living and international instability caused by the war in Ukraine.
The constitutional monarch, who is supposed to remain outside politics, has intimated he will now steer clear of pronouncements on issues that he has previously been outspoken on such as climate change.
British Prime Minister Liz Truss -- only appointed by the late monarch on Tuesday -- offered the nation's support to Charles in parliament on Friday as she acknowledged the "awesome responsibility" upon Charles.
The speaker of the House of Commons and selected senior MPs swore allegiance to the new king on Saturday and Charles met Truss again, plus the cabinet and the heads of the opposition parties.
Buckingham Palace revealed Charles and other members of the royal family would observe an extended mourning period from now until seven days after her funeral.
The funeral will be attended by heads of state and government, with US President Joe Biden among those who said they will come.
British security officials are planning what has been dubbed likely the "biggest policing and protective operation" in UK history as London gears up to host leaders from across the globe.
The Kremlin said Russian President Vladimir Putin -- at loggerheads with the West over his invasion of Ukraine -- will not attend.
But Putin did offer Charles "his sincerest congratulations", adding: "I wish Your Majesty success, robust health and above all the best."
While the government has said there is no obligation on organisations to suspend business during its 10-day mourning period, many are doing so out of respect.
England's Premier League postponed all matches this weekend, while railway and postal workers called off strikes over pay amid soaring inflation and spiralling energy prices.
English cricket however bade farewell to the queen as the Oval ground fell silent when play resumed in the test match against South Africa after being halted following her passing.
Elizabeth's body has so far remained at her beloved Scottish retreat of Balmoral where she died and will be transported by road to the Palace of Holyroodhouse in Edinburgh on Sunday.
Senior royals including the queen's other children Princess Anne and Princes Andrew and Edward also greeted well-wishers outside Balmoral on Saturday.
Prince Andrew -- who has also stepped back from public duties over allegations, strongly denied, that he had sex with a teenage victim of convicted sex US offender Jeffrey Epstein -- thanked the public for their condolences.
"We've been allowed one day, now we start the process of handing her on," he said.
On Monday, the coffin will be taken in procession along the Royal Mile to the magnificent St Giles' Cathedral, where a service will be held.
From the Scottish capital, it is due to travel to London on Tuesday to lie in state for four full days in Westminster Hall, the oldest building in parliament.
Officials expect more than one million people to attend to pay their respects, before the televised funeral service at Westminster Abbey opposite.
The funeral for the queen -- who came to the throne aged just 25 in 1952 -- will be a public holiday in the form of a Day of National Mourning.
Charles's coronation, an elaborate ritual steeped in tradition and history, will take place in the same historic surroundings, as it has for centuries, on a date to be fixed.