Most brides have feelings of excitement tinged with nerves the night before their wedding.

And it seems that Princess Diana was no exception the day before her marriage 40 years ago.

She spent the night before the ceremony at Clarence House before tying the knot with Prince Charles at St Paul's Cathedral in front of a huge global audience.

With crowds beginning to form in London the day before the ceremony, there was a buzz around the city as night began to fall.

And understandably, this meant Diana was far too excited and nervous to sleep.

So to release her emotions, she jumped on a bike, rode it around in circles and sang: "‘I’m going to marry the Prince of Wales tomorrow!"

Prince Charles and Princess Diana on the balcony of Buckingham Palace on their wedding day (

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The story was revealed in the book The Diana Chronicles, written by former Vanity Fair editor Tina Brown.

She says that with Diana unable to rest, she went downstairs to speak with the Queen Mother's former steward William Tallon, also known as Backstairs Billy and to get a drink.

But on her way, she spotted a bike in the corner of the room and jumped on it before riding it around in circles and ringing the bell as she sang out.

Meanwhile, despite reportedly having doubts about his marriage, Prince Charles wrote his bride a sweet and supportive note the night before the wedding.

In her book about Camilla, royal author Penny Junor writes: "The night before the wedding, which Diana spent at Clarence House with her sister Jane, he sent her a note, along with a signet ring that bore the Prince of Wales feathers.

Charles and Diana greet the crowds on their wedding day from the balcony of Buckingham Palace (

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Getty Images)

"He wrote: "I'm so proud of you and when you come up I'll be there at the altar for you tomorrow. Just look 'em in the eye and knock 'em dead'", reports the Express.

Ms Junor also claims Charles believed the wedding was a mistake but knew it was too late to pull out.

A year after their fairytale wedding, Charles and Diana welcomed Prince William and later Prince Harry but the couple separated in 1992 after their marriage broke down.

The couple divorced in 1996, just a year before Diana tragically died following a car crash in Paris.