The Princess of Wales will no doubt be surrounded by her nearest and dearest today as she celebrates a special occasion - her 42nd birthday.
Over the years, Prince William has treated her to many special gifts and there's no doubt that her three children - Prince George, Princess Charlotte and Prince Louis - will be doing all they can to make the day more memorable. However, there is one birthday that Kate might want to forget - that's when she turned 27 and was forced to say an emotional goodbye to her future husband after he made a decision that left her "crushed".
William and Kate at his RAF graduation in 2008 (Tim Graham/Getty Images)
The couple on Christmas Day with their three children (PA)In September 2008, when rumours started to circulate that William was ready to pop the question, it was officially announced that he was to join the RAF - a decision that came as a surprise to his family and his girlfriend.
Having just completed assignments with each section of the Armed Forces, William had two choices - to return to the Household Cavalry or quit the forces and begin his royal duties. For William, the RAF career path would allow him extra time and freedom before starting his royal journey full-time, giving him an independent life that his grandmother and father were denied. But for Kate, it was apparently a step backwards as everyone was expecting her to marry the prince and start her royal life.
In her book, Kate: The Future Queen, royal expert Katie Nicholl writes: "With that single decision, Kate's life was turned upside down. She had expected a proposal once William had completed his military training, but instead, she was forced to accept that there would be no engagement any time soon. Kate would have to wait even longer."
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William's new job would involve 18 months of training in Shropshire followed by two years at a remote location somewhere in the UK. Katie writes: "Was Kate prepared to join him? She supported his desires and ambitions, but privately she was crushed. William was asking her to be an army wife - without the nuptials. Her frustration was understandable."
In the weeks that followed Kate and William spent some quality time together in Scotland, where they stayed for New Year, and Kate went on holiday with her family, but by the time her birthday came around it was time for the next stage in the prince's life to begin in the RAF. Katie writes that William was confident their relationship would survive the long distance, with the Shropshire base around three hours away from London.
The Princess of Wales turns 42 today (PA)But she claims that Kate found it even harder as all their friends were settling down and she was being left behind. She writes: "For Kate, it was a step backwards. It seemed that everyone was getting married except for her. As she neared her 27th birthday, Kate's plan to be married with children by the time she was thirty was looking increasingly unlikely."
However, the pair did manage to make it work and William would regularly make the 130-mile drive back to Bucklebury to see Kate at her parent's house. And at the end of 2010, William finally made things official, getting down on one knee and popping the question. The rest they say is history, as months later they married at Westminster Abbey and almost 11 years on are the parents to three gorgeous children.