King Charles caught complaining to Camilla ahead of Saturday's coronation
The King was caught on camera grumbling to Queen Camilla, telling her "this is boring", as he waited to enter Westminster Abbey for his own coronation.
The monarch arrived at Westminster Abbey ahead of schedule on Saturday morning and had to wait outside for five minutes before entering the church.
The Prince and Princess of Wales and Princess Charlotte and Prince Louis were late and, unable to overtake to get ahead of the King, joined his procession through the church.
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With the world watching his every move, one expert lipreader told Sky News what the King was saying to Camilla at the time.
"We can never be on time," he appears to tell Camilla.
"There's always something... this is boring."
It could have simply been nerves ahead of his crowning moment, with the King crowned in an historic ceremony - a fulfillment of Charles's destiny after the death of the late Queen.
Both royals were crowned in a ceremony watched by 100 heads of state, royals from around the world, celebrities, everyday heroes, and millions around the globe.
Things 'didn't go strictly to plan'
While it was a historic service steeped in tradition, "there were one or two things that didn't go strictly to plan," one bishop said after the service.
Speaking outside St Margaret's Church next to Westminster Abbey, the Bishop of Chelmsford, Dr Guli Francis-Dehqani, 56, said: "I'm not going to embarrass anyone in particular."
During the service, the Archbishop of Canterbury spent several seconds adjusting the crown as the King was officially crowned.
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As St Edward's Crown was placed on the King's head, there was complete silence in Westminster Abbey as the congregation stood for the occasion. The archbishop placed it on the King's head firmly, before giving it a twist in an attempt to keep it on. But after the twist failed to work he lifted the crown up again, before having another go at securing it in position.
After his second attempt, the crown tipped forwards on the King's head.
Archbishop Welby then tilted it to the side before he was happy to remove his hands from the crown. The archbishop then leaned forward toward the King and carefully inspected the crown before eventually retreating.
The official crowning of the King took about eight seconds in total.