Britain's King Charles III has made his first televised address since ascending to the UK throne following the death of his mother Queen Elizabeth II.
He said he was brought up to "cherish a sense of duty to others" and pledged to honour the queen's "life of service".
He said his "darling mama" had devoted her life to the service of her people.
"Queen Elizabeth was a life well lived; a promise with destiny kept and she is mourned most deeply in her passing," the king said in the opening moments of his address, which he delivered with a photograph of her displayed next to him.
"That promise of lifelong service I renew to you all today."
Charles also used his speech to announce that he had made his son, William, the Prince of Wales, while Catherine has become the Princess of Wales.
He also expressed his "love for Harry and Meghan as they continue to build their lives overseas", a symbol of his bid for reconciliation amid past troubles with the Sussexes.
Charles said of the late queen: "We owe her the most heartfelt debt any family can owe to their mother; for her love, affection, guidance, understanding and example."
He added: "To my darling Mama, as you begin your last great journey to join my dear late Papa, I want simply to say this: thank you.
"Thank you for your love and devotion to our family and to the family of nations you have served so diligently all these years. May 'flights of Angels sing thee to thy rest'."
Earlier, Charles hosted Prime Minister Liz Truss at Buckingham Palace for their first formal audience as he starts his reign after the death of Queen Elizabeth II.
A palace spokesperson said that the meeting took place after the king returned to London from the royal family's Scottish retreat Balmoral, where his mother passed away yesterday.
On his arrival at Buckingham Palace earlier, the new king greeted crowds who were gathered outside, in his first walkabout and encounter with the public since his historic accession.
Crowds clamoured to meet Charles at the barriers, with people taking photographs and shaking his hand after he emerged from his state Bentley.
His wife Camilla, the queen consort, followed at a distance behind him, before joining his side to view the large collection of brightly coloured floral bouquets left in tribute to his mother.
Shouts of "God Save the King" went up, along with three cheers, for Britain's new head of state, dressed in mourning black suit and tie, who smiled and waved at the mass of people.
King Charles and wife Camilla were later cheered again after they left Buckingham Palace.
As well as the palace, the queen's other residences in Windsor Castle and Balmoral continue to attract thousands of people wanting to pay their respects to the late monarch, with hundreds of bouquets, personal notes and candles being placed in her honour.
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Details of Charles' historic Accession Council, which will be held tomorrow at 10am in St James's Palace, were announced by Buckingham Palace.
It will be televised for the first time in its history, showing the late queen's eldest child being formally proclaimed as Britain's monarch and Charles making his declaration and oath.
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A Principal Proclamation will be read in public for the first time by the Garter King of Arms in the open air from the balcony overlooking Friary Court at St James's an hour later at 11am.
It will be followed by a flurry of proclamations including in Scotland, Northern Ireland and Wales at midday on Sunday.
Prince William is also travelling back to Windsor to be with his family ahead of the Accession Council, which he will attend.
Charles and Camilla made the poignant journey from Balmoral today, where the queen died peacefully on Thursday at the age of 96, arriving at RAF Northolt in west London at around 1.35pm.
Tributes continue to be paid to the woman described by Liz Truss as the "rock on which modern Britain was built", with the Dalai Lama expressing his "deep sadness" over the queen's death in a letter to Charles.
He stated: "Your mother lived a meaningful life with dignity, grace, a strong sense of service and a warm heart, qualities we all should treasure."
Charles has already turned his hand to his duties. He gave the order that a period of "Royal Mourning" for the queen will be observed in Britain from now until seven days after her funeral.
