Queen Elizabeth's grandson and his wife Meghan, the Duke and Duchess of Sussex, have announced they will step down from their duties as senior royals next month to spend more time in North America.
Although Harry will no longer be known as His Royal Highness, he will still be a Prince.
But before his speech on Wednesday (February 26), event host Ayesha Hazarika told delegates: "He's made it clear that we are all just to call him Harry."
Harry and Meghan have been in Canada with their son Archie for several weeks but Harry came back to Britain on Tuesday (February 25), according to local media.
On Friday (February 28), he is due to visit the studios at Abbey Road in north London, where the Beatles recorded 11 of their 13 albums, to meet the singer Jon Bon Jovi and the Invictus Games Choir, who are recording a single for charity.
His trip to Britain comes after news last week that he and Meghan would not use the word "royal" in their branding, following weeks of talks between the couple and the royal family about how they will present themselves to the world in future.