Prince Harry asked to be introduced as just "Harry" at an event on Wednesday, kicking off a final round of public engagements before he and wife Meghan step back from their royal duties.
The Duke of Sussex, a grandson of Queen Elizabeth II, will stop using "His Royal Highness" from the end of March when the couple stop being working royals.
But at a conference in Edinburgh for his sustainable tourism project Travalyst, it emerged he was already adopting a more informal approach.
"He's made it clear that we are all just to call him Harry, so ladies and gentlemen -- please give a big, warm Scottish welcome to Harry," host Ayesha Hazarika said in her introduction.
The 35-year-old prince has faced accusations of hypocrisy for using private planes while advocating action to combat global warming but he insists he mostly travels via commercial flights.
He used his remarks in Edinburgh to warn of the risks of huge increases in tourists at key locations, which he said could cause pollution, overwhelm local communities and drive out wildlife.
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As sixth in line to the throne, Harry's announcement in January that he and his wife wanted to step back from their royal positions rocked the monarchy.
The pair revealed plans to split their time between Britain and Canada, after complaining about media intrusion and expressing a desire to be financially independent.
Harry arrived in Edinburgh by train on Tuesday evening without Meghan or their baby son Archie.
On Friday, he will be in London to meet US rock singer Jon Bon Jovi, who is recording a special song for the prince's Invictus Game Foundation for military veterans.
They will meet at Abbey Road Studios, where The Beatles recorded most of their albums and where Bon Jovi is also recording his song with a choir made up of wounded veterans and serving personnel.
In a BBC interview this week about the event, the singer quipped that following his exit from frontline royal life, Harry should be known as "the artist formerly known as Prince".
The musician Prince took this title after eschewing his name in favour of a symbol.
Harry and Meghan will join the queen on March 9 for a Commonwealth Day service at Westminster Abbey, which is expected to be their last official appearance as working royals.