Queen Elizabeth II dies - follow the latest news as the world mourns
In a statement released on Monday, which is understood to have been held back a day out of respect for the anniversary of the September 11 attacks in the US, the Duke of Sussex also said he wanted to honour his father at the start of his reign as King Charles III.
Referring to the queen as "Granny", he said it made him smile to know that she has been reunited with "grandpa", the late Duke of Edinburgh who died last year.
He also revealed that the Queen shared precious moments with his children just a few months before her death.
The prince described how the queen hugged Archie, three, and Lilibet, 15 months, likely when the family visited the UK in June to attend the queen’s platinum jubilee celebrations.
At the time, it was not known if the Sussexes had met privately with the queen during their stay at their Frogmore cottage home close to Windsor Castle.
“In celebrating the life of my grandmother, Her Majesty The Queen — and in mourning her loss ― we are all reminded of the guiding compass she was to so many in her commitment to service and duty," Harry said.
“She was globally admired and respected. Her unwavering grace and dignity remained true throughout her life and now her everlasting legacy.
“Let us echo the words she spoke after the passing of her husband, Prince Philip, words which can bring comfort to all of us now: ‘Life, of course, consists of final partings as well as first meetings.'”
He added: “Granny, while this final parting brings us great sadness, I am forever grateful for all of our first meetings ―from my earliest childhood memories with you, to meeting you for the first time as my Commander-in-Chief, to the first moment you met my darling wife and hugged your beloved great-grandchildren.
“I cherish these times shared with you, and the many other special moments in between. You are already sorely missed, not just by us, but by the world over.
“And as it comes to first meetings, we now honour my father in his new role as King Charles III. Thank you for your commitment to service. Thank you for your sound advice.
“Thank you for your infectious smile. We, too, smile knowing that you and grandpa are reunited now, and both together in peace.”
The queen and Duke of Edinburgh saw Archie at Windsor Castle a few days after he was born in May 2019 but it was thought the Queen had not held Lilibet, who was born last June.
Her great-granddaughter was named after her – taking her childhood nickname.
The statement came two days after the duke and his wife Meghan, the Duchess of Sussex, joined the new Prince and Princess of Wales at Windsor Castle on Saturday.
The princes have a well-documented troubled relationship but the death of their grandmother saw the pair shelve their differences when, with their wives, they viewed floral tributes left to the late queen.
It is understood Prince William invited his brother to join them in meeting well-wishers outside the castle as an “important show of unity”.
Two years have passed since the four were together side by side in public, during the 2020 Commonwealth Day church service. On Saturday, they appeared at ease driving off together with William at the wheel of a Range Rover after their walkabout lasted a little more than 40 minutes.
During their walkabout, the Duchess of Cambridge told children who had gathered to lay flowers that her son, Prince Louis, had responded to the death of the queen by saying: "At least granny is with great grandpa now."