British royal Prince William managed to get just 30 minutes' sleep on the eve of his wedding to Catherine, Duchess Of Cambridge last year (11).
The second-in-line to the throne stayed at royal residence Clarence House in London the night before the ceremony but his excitement - and the cheering crowds outside his home - left him unable to sleep.
Speaking on new documentary Elizabeth: Queen Wife Mother, "I hadn't slept at all that night because obviously all the crowds were on The Mall. They were singing and cheering all night long. So, the excitement of that, the nervousness of me, and everyone singing meant I slept for about half an hour. So when I did get up in the morning, I can say that I had prepared myself totally by that point.
"It was a case of just going out there and trying to enjoy the moment and also get through it. But it was good fun - it was really good fun."
The prince also admits his struggles continued the next day - he was concerned he'd take a tumble due to the metal spurs attached to the boots of his Irish Guards uniform.
He says, "The hardest thing was trying to walk down the stairs with my spurs on, sideways. I had visions of myself and my brother Harry colliding and crashing down the stairs together."