Prince Charles reportedly gave Prince William a fatherly pep talk before he entered the University of St. Andrews in Scotland.

In the book “William’s Princess,” royal author Robert Jobson detailed the conversation that the father and son had almost two decades ago. He said that while Prince William’s peers were worried about what their classmates might think, the Duke of Cambridge was concerned with the nation might think of him.

Prince Charles reminded Prince William of the importance of being discreet. The heir to the throne also encouraged his son to choose his friends wisely.

“The ground rules, he said, were very simple: no drugs, no getting caught in compromising positions with girls, no kissing in public, no excessive drinking and no giving his bodyguards the slip.  Charles warned his son in solemn tones about the dangers of falling in with the wrong girls and of the excruciating consequences of being caught on the wrong end of a kiss-and-tell sting,” Jobson said.

During his time at the university, Prince William rarely let his guard down. And during his pre-university press interview, Kate Middleton’s husband said that he knows how to tell if the person is sincere or is just using him because of his royal status.

It was also at the University of St. Andrews that Prince William and Middleton first met. Before getting into a relationship, the Duke and Duchess of Cambridge started off as friends. In fact, they also lived in the same apartment with two of their pals.

Very early on, Middleton was already vocal about her fondness for Prince William. Her friend, Jessica Hay told Jobson that the Duchess of Cambridge had a crush on her husband long before Prince William noticed her.

“We would sit around talking about all the boys at school we fancied but Catherine would always say, ‘I don’t like any of them. They’re all a bit rough.’ Then, prophetically, she would joke, ‘There’s no one quite like William.’ She had a picture of him on her wall. It was one of him and his father fishing, but she had cut off Prince Charles. She always used to say, ‘I bet he’s really kind. You can tell by just looking at him.’ We always said that one day she would meet him and they would be together,” Hay said.

Prince William and Middleton’s relationship lasted for almost 10 years before they decided to tie the knot.