Queen Elizabeth II: Prince Harry calls grandmother 'guiding compass'
In his first public comments since the queen's death last week aged 96, Harry said he was "forever grateful" to her and said she was "sorely missed".
Harry and his wife Meghan stunned the monarchy by announcing they were quitting royal duties and moving to the United States in early 2020.
From there, they launched a series of broadsides criticising their life in the institution, including allegations of racism.
That exacerbated tensions with his older brother, heir to the throne Prince William – with whom he is reported to be barely on speaking terms – and their father, now King Charles III.
But Harry, who was on a whistlestop visit to Britain with Meghan when the queen died, was handed an olive branch by Charles in his first speech as king, when he spoke of his "love" for the couple.
William also invited his brother and sister-in-law to join them for an impromptu walkabout to view floral tributes at Windsor Castle on Saturday.
Harry, a former British Army captain who served in Afghanistan, said the queen was his commander-in-chief but also his "granny".
He said he would cherish the memory of the first time she met Meghan and hugged the couple's young children, Archie, aged three, and Lilibet, one.
"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," he added.
"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 [Prince Philip] are reunited now, and both together in peace."
Harry and Meghan jetted in from their new home in California last week to attend a series of charity functions in Britain and Germany, where the next Invictus Games for disabled veterans takes place.
Queen Elizabeth II joined her grandson in a 2016 spoof video before the first edition of the multi-sports event, poking fun at playful jibes from the former US President Barack Obama and his wife, Michelle.
The video indicated a close relationship between Harry and his grandmother, which persisted despite the bombshell announcement that he was leaving royal life.
She allowed the couple to retain their official titles as the Duke and Duchess of Sussex and said they would remain "much-loved members of the family".
The late monarch also held back from publicly rejecting the couple's claims of racism, stating that "some recollections may vary", but promising an investigation.
Harry rushed to the Balmoral estate in the Scottish Highland last Thursday after an announcement about the queen's health.
But he travelled separately from his brother and other senior royals, arriving several hours after the death was announced.
Harry, who is expected to stay in Britain for the queen's funeral next Monday, is believed to have last met her in private during the public celebrations for her Platinum Jubilee in June.