Marcia Moody, in her 2013 book “Kate: A Biography”, describes how Prince William had the idea to go out with Prince Harry into the crowds thronging around Clarence House, Green Park and Buckingham Palace the night before the big day.
She writes: “It was a very modern gesture by a member of the Royal Family, and very typical of William.”
However, the loud and excited crowds actually prevented the nervous bridegroom from sleeping that night.
Prince William later recalled: “The crowds were singing and cheering all night long, so the excitement of that, the nervousness of me and everyone singing – I slept for about half an hour.”
Although Ms Moody writes, the Duke of Cambridge was “a little more sensible that night” than his brother Prince Harry.
After staying up drinking with Pippa Middleton and his then-girlfriend Chelsy Davy, Harry left the Goring Hotel at around 3am by jumping off a balcony into a flowerbed, before walking back to Clarence House.
Nevertheless, Prince Harry performed his best man duties admirably on the wedding day, with a few surprises up his sleeve for the newly-weds.
In addition to decorating Prince Charles’ Aston Martin, that William whisked Kate away from Buckingham Palace in, he also transformed the throne room for the couple’s evening reception.
Plus, his cheeky idea to entertain the little bridesmaids and pageboys on the day even managed to sneak its way into the official wedding photos.
Harry also gave a touching best man’s speech at the couple’s wedding reception that made Kate “shed a tear”.
Royal author Katie Nicholl, in her 2017 biography “Harry: Life, Loss and Love”, writes: “It was affectionate, warm and funny and touched William deeply.
“When he said the couple’s decade-long romance was his inspiration, there was a shy smile from Chelsy, while Kate shed a tear.”