Catherine, Duchess of Cambridge, aka Kate Middleton, was a mousy bookworm at age 16 in 1998 until she decided it was time to emerge from her mild-mannered cocoon.

Wanting to be noticed while attending Marlborough College, a boarding school in Marlborough, Wilshire, England, she opened her second-story dorm window and flashed her nude bum to male students in view.

Cheers from the grateful crowd encouraged her mooning and it evolved into an obsession she took great pride in and earned her the moniker of ‘Kate Middlebum’.

‘She kind of got addicted to it,’ her close schoolmate, Jessica Hay stated. Over the course of one year, she put her bare bum in the window for anyone to see no less than 90 times.

While she was quickly coming out of that shy cocoon, she didn’t have her first lover yet, Christopher Andersen writes in Game of Crowns: Elizabeth, Camilla, Kate and the Throne, published by Gallery Books.

What a transformation! Kate Middleton went from a gawky kid to a stunning woman. At 20, Kate knew how to dress to impress – men.  She wanted to be noticed while attending Marlborough College, a boarding school in Wilshire, England, so she flashed her nude bum to any male students in view

Coupling: When she met William at St Andrews their first encounter was ‘awkward and mercifully brief’ but before long they became friends and then flatmates

Steamy:  Williams was watching when Kate modeled on catwalk at student fashion show with Fergus Boyd, both flatmates of  the prince at St Andrews

Kate met Prince William three years later in 2001. The encounter was ‘awkward and mercifully brief’ at their dormitory at St. Andrews, the oldest university in Scotland, which they both attended.

She ‘turned bright red and sort of scuttled off, feeling very shy about meeting him’, Kate recalled.

He was the very reason she was there: to meet, and with any luck, to marry the future monarch, Andersen writes.

Kate had harbored a crush on Princess Diana’s oldest son for years and displayed a color photo of him with his father, Prince Charles, in her bedroom at Marlborough College, says the author.

She tracked Will’s royal schedule, read every newspaper and magazine story including every gossip item.

‘You cannot tell me anything about Prince William that I don’t already know,’ she told a schoolmate.

Like mother, like daughter: Kate’s mother, Carole Goldsmith was six years older than Diana, and her youthful fixation was on William’s father, Charles, the Prince of Wales.

But there wasn’t even a remote chance their paths would ever cross.

Growing up, Carole’s family moved from a cramped, unheated flat in London’s downscale Southall to a larger house in the nearby area of Ealing, decidedly more affluent but not any closer to her fantasy Prince.

Flirty: Kate Middleton and Lord Frederick Windsor look cozy as they attend a shop opening in 2006

Jealous? Kate and William had split when this picture of Kate with an unknown friend was taken at a performance at Wembley stadium in 2007

She had neither the means nor the desire to attend college and joined the British Airlines flight attendant program right out of high school in 1974.

She met Mike Middleton, head of ground operations at Heathrow Airport, and they married in 1980.

Lest those princely fantasies evaporate, she transferred them to her daughter, Catherine who was born on January 9, 1982, six months before Prince William’s birth on June 21 that same year.

With luck and hard work, the Middletons mail-order business, Party Pieces, that created anything one would need for a proper children’s party, gave them the income to move even closer to fulfilling that princely fantasy for their daughter.

They now had the money to send Catherine to a private school – where there might be a prince in residence.

When she was seven she was enrolled at St. Andrew’s School in the nearby town of Pangbourne.

Kate was great at sports as well as academics and at that age expressed a fondness for dressing up. She sang the lead in the school’s musical productions.

At thirteen, Kate was enrolled in Downe House, an all-girls boarding school in the town of Cold Ash, Berkshire, near the Middleton home.

She was a gawky, skinny kid. She was bullied, and when it didn’t stop, her mother transferred Kate to Marlborough College, her first co-ed school experience.

‘Her looks were judged a ‘2’ on a scale of 1 to 10 by a group of tittering adolescent boys – from the moment she walked into the school’s dining hall’.

While at Marlborough, Kate was reading those tabloid stories about all the eligible young women circling the future king. That event included a schoolmate of Kate’s.

More 𝓈ℯ𝓍y photos appeared of Kate when she joined an all-female rowing crew, the Sisterhood, which was planning to row across the English Channel. She dropped out after being photographed training

Wills was every English girl’s dream and was even carrying on lusty emails with President George W. Bush’s niece, Lauren Bush and even racier emails with pop star Britney Spears.

Kate had already made up her mind to attend the University of Edinburgh in pursuit of a degree in art history and that school had a particularly strong arts curriculum.

Wills, originally intent on Edinburgh as well, changed his plans to attend St. Andrews.

Carole Middleton’s lobbying efforts to convince Kate to switch went into high gear when she learned that a former Marlborough student, Mili d’Erlanger, was following Wills to St Andrews, claims the author.

‘St. Andrews offered something no other university in the world offered: proximity to the future King of England’.

Kate was on board with the switch but she wasn’t the girl Wills fell for at first. He was charmed by her friend, Carly Massy-Birch, the daughter of a Devon farmer.

That relationship was preceded by a sizzling summer romance with Arabella Musgrave who ended their affair when she realized William had a ‘roving eye’.

He kept up pursuit of ‘Bella’ while seeing Carly but she had called it quits.

Kate was less aggressive in the dating department. Early on at St. Andrews, she was attracted to Rupert Finch, the tall, dark-haired star of the school’s cricket team but that romance was winding down.

Kate belonged to Sally’s Boys, a group from a student resident hall that also included the Prince’s inner circle.

Michael and Carole Middleton With luck and hard work, Michael and Carole Middleton’s mail-order business, Party Pieces,  gave them the income to move even closer to fulfilling that prince fantasy for their daughter

William and Kate were both into sports and as friends, cycled together at the beach on weekends, swam laps together at the Old Course Hotel pool.

If William missed a class, Kate shared her notes with him.

And there was the occasional drink at a bar or a late-night karaoke session at one of the student hangouts.

The couple became close friends and the Prince paid two hundred pounds for a front-row seat when Kate participated in St. Andrews University’s annual Don’t Walk charity fashion show sponsored by Yves Saint Laurent in March 2002.

Kate decided on wearing a sheer black, gold and green garment trimmed in blue ribbon.

She slipped into the bandeau bra and black bikini panties and pulled the shift over her head with the top edge right above her breasts. It was a floor-length skirt but Kate kept it as a top so that the hem came to her mid-thigh.

A dresser tried to correct her to pull the skirt down but Kate refused.

‘I like it this way. This is much 𝓈ℯ𝓍ier.’

And she hit the catwalk in what looked to be a naughty, highly erotic negligee.

‘William clapped and cheered the loudest’ and then whooped and whistled when she returned to the catwalk after a change into a white lace bra and white lace panties.

‘It was a side to her we didn’t know existed, and it was a turning point in people’s perception of her,’ classmate Jules Knight said. ‘Everyone took note, including Will.’

As swimmingly as their relationship was going, Camilla, the Rottweiler as she was dubbed by Princess Diana, stepped in and whispered to her then lover, Prince Charles, that she had misgivings about Kate’s working-class roots and that William best be looking for a future bride among the daughters of their aristocratic friends, claims Andersen.

Closer to the truth was that Camilla was ‘disgusted with William and Kate sucking up all the attention’, a former Clarence House staffer said.

‘Charles and Camilla needed the love of the people and they figured there is only so much love to go around’.

Camilla Parker Bowles was not on Team Kate – she didn’t think Kate and her family were up to royal standards, claims Andersen

Charles found the courage to tell William to break it off with Kate and on April 11, 2007, William ended their six-year romance in a cellphone call says Andersen.

After marrying Prince Charles in 2005, Camilla became the second-ranking female in the kingdom and she had been closely following William’s romantic affairs.

She also used investigative sources available to her through the Palace to learn as much as she could about Kate’s working-class background and she was most unimpressed.

The Goldsmiths, Kate’s mother’s family was working class – ‘two-fisted, hard-drinking denizens of County Durham’s coal fields in northeastern England’.

‘Kate’s great-great-great-grandfather was thrown in jail for public drunkenness in 1881; her great-grandmother Edith, left to raise six children in a condemned flat following the death of her husband, worked long hours in a pickle factory.

‘Many of her maternal ancestors succumbed to influenza, scarlet fever, cholera, or fell on the battlefield during World War I’.

Kate’s father’s side of the family was more promising.

The Middletons were related to English actor, Sir John Gielgud; author and illustrator Beatrix Potter of Peter Rabbit fame; Britain’s leading Shakespearean actress, Ellen Terry; and through Sir Thomas Fairfax, a seventeenth-century statesman somehow connected to the Royal Family.

Kate bared her belly on an outing with her father Michael Middleton before her graduation ceremony at the University of St. Andrews in 2005

That connection made Kate and William fifteenth cousins.

Carole Middleton, by all reports, writes the author, was gauche and pushy and an unrepentant chain smoker who turned to chewing gum when she couldn’t light up.

Camilla had blown smoke in plenty of faces for fifty years and now ‘she couldn’t stand to see anyone else smoke’.

She claimed the smell made her sick.

Getting beyond Kate’s working class background, her opinion of Kate was ‘pretty, but rather dim’.

‘Beneath it all’, stated a friend of Parker Bowles, ‘Camilla is a snob. Her family has always moved in royal circles. It’s simply second nature to her. She simply felt Kate and the Middletons were too lowly to marry into the Royal Family’.

Camilla waited more than thirty years to be accepted by the Queen. She was married to Andrew Parker Bowles and simply Prince Charles’ lover.

‘She wasn’t going to have someone just march in and sort of drag the whole thing down,’ writes Andersen.

But more to the point, she had come to love the limelight after all those years of being the other woman who met her lover secretly in the shadows.

Kate was naturally pretty, young, everything Camilla wasn’t and she became consumed with jealousy, says the author.

‘It only makes sense that Camilla resented being eclipsed by a beautiful young woman like Kate Middleton. Maybe she felt threatened by Kate, or perhaps more by William and Kate as a team’.

When William broke it off with Kate, her response was to hit the London social scene and go clubbing with her sister, Pippa, even more stylish than her older sister.

The tabloids couldn’t get enough of the girls’ nights out and they went into high gear to get photos of them at William’s favorite London hangouts.

Kate didn’t care. She openly flirted with other men.

More 𝓈ℯ𝓍y photos appeared of Kate when she joined an all-female rowing crew, the Sisterhood, which was intending to race against the all-male Brotherhood in a twenty-one-mile race across the English Channel. She was always wearing tight racing outfits, standing at the stern of the boat.

Her Windsor-in-waiting wardrobe lost out to miniskirts and skin-tight designer jeans.

Kate was 𝓈ℯ𝓍ier without Wills who ‘suddenly felt like he had made a huge mistake’.

Six weeks after breaking off with her, he apologized and they were back in each other’s arms.

William proposed in October 2010 by a glistening lake nestled on the slopes of a snow-capped Mount Kenya at 12,500 feet above sea level.

He got down on bended knee and proposed with his mother’s famous eighteen-carat sapphire and diamond engagement ring – ‘my way of making sure my mother didn’t miss out on today’.

On April 29, 2011, the wedding of the century took place at Westminster Abbey and cost an estimated $34 million.

It was the biggest media event of the twenty-first century and was estimated to have been watched on television and via the internet by some three billion people.

The Queen issued some new rules after Kate and William married and one states that Kate need only curtsy to Camilla when William is with her.

But before William can ascend to the throne, the House of Windsor will have to survive the reign of Charles III and Camilla.