Royal expert says 'nobody expected' Prince William and Kate Middleton's relationship to last

Prince William and Kate Middleton are one of the most famous couples in the world and have amassed an enormous royal fanbase over the years - be it for the fact that they talk openly about life behind closed doors with their three little ones, Prince George, Princess Charlotte and Prince Louis, or for their sweet moments together when they're out in public.

The couple met at university, becoming close friends before they eventually started dating - but one royal expert claims that 'nobody expected' the pair to go the distance once they left St Andrews.

Royal biographer Andrew Morton, who has written a number of books on the family including Diana: Her True Story and Meghan: A Hollywood Princess, claims that many of those at the Palace weren't convinced that their relationship would survive past university.

He told OK! magazine: 'In the beginning, nobody expected for a second that the university romance with Catherine and William would continue for any time after they graduated, like most college romances which disintegrate under the intense scrutiny of jobs and geography.

'After he left college, William was doing all kinds of jobs, to get a sense of the Britain he will take over. Catherine was left to go her own way, but she survived.'

While they continued to date after university, the Cambridges did split briefly in 2007 - although according to royal expert Kinsey Schofield, it only secured Kate's place in the family fold as 'future Queen'.

She has previously told the Express that during their break-up that the Palace 'knew she was a good girl, they knew she wasn't talking to the media' and her 'stoic' nature made Kate a 'no-brainer' when it came to taking on such an important future role in the royal family.

The Duchess of Cambridge has become one of the most influential royals according to insiders, with many claiming that she 'holds the future of the monarchy in her hands'.