The Duke of Sussex, 37, will appear alongside several other members of the Firm as they look back at the life of the Duke of Edinburgh. The UK’s national broadcaster will air Prince Philip: The Royal Family Remembers on Wednesday at 9pm.
It was initially commissioned to mark the Duke’s 100th birthday, which would have been celebrated on June 10.
But Prince Philip, who was Britain’s longest-serving consort, passed away in April, aged 99 after spending 73-years married to Queen Elizabeth II.
Looking back at the relationship between his grandmother and grandfather, Prince Harry said: “The two of them together were just the most adorable couple.”
The estranged Duke added: “I don’t know if anyone’s ever described them as adorable but, to me, knowing the cheekiness of him and knowing that behind what the world sees you have two individuals who were very much in love, and both at a very young age dedicated both of their lives to service.
“The places these two travelled, the things they saw, the experiences they went through.
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“That is an incredible bond between two people.”
The close relationship between the Queen and her late husband has been well-documented since the Duke’s death in April.
When Buckingham Palace released a statement confirming Philip had passed away, they said: “It is with deep sorrow that Her Majesty The Queen announces the death of her beloved husband, His Royal Highness The Prince Philip, Duke of Edinburgh.”
On the Queen’s 95th birthday, she added: “While as a family we are in a period of great sadness, it has been a comfort to us all to see and to hear the tributes paid to my husband, from those within the United Kingdom, the Commonwealth and around the world.”
Harry went on to claim he will miss his grandfather mostly for his sense of humour.
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“He used to get into a lot of trouble from my grandmother for covering most of the places we had lunch and things with mustard on the ceiling.”
The Duke of Cambridge added: “He enjoyed those jokes, he enjoyed messing around with the children, and kind of being a grandfather.”