Katie Nicholl wrote in her book The Making of a Royal Roman that William and Kate did not spend Christmas together in 2006.
The reason for that was because, although they had been dating for five years, only married couples were invited to the Queen’s Sandringham celebrations.
According to Nicholl, William reportedly made “big plans” for the New Year to make up for not spending Christmas with his then-girlfriend.
However, the young Prince changed his mind and on Boxing Day, he cancelled the plans, and told her he’d be staying with his own family instead.
The royal author said that despite dating for several years, Prince William was wary of taking the next step with Kate because of his royal status and his own parents’ difficult marriage.
She said: “William had been having second thoughts and sat down with his father and his grandmother to have a frank discussion about his future with Kate. Both advised him not to hurry into anything.”
In April 2007, the news broke that Kate and William had broken up, with sources saying the Queen was “disappointed” by the news.
However, they were seen together at an army party at barracks in Bovington, Dorset, just weeks later.
In 2010, the royal couple announced their engagement to the public, and in her first-ever TV interview, Kate said she “wasn’t very happy” about their brief split but that it actually made her a “stronger person.”
She said: “You find out things about yourself that maybe you hadn’t realized.”
William agreed and added: “It was very much trying to find our own way and we were growing up so it was just a bit of space, and it worked out for the better.”