William candidly admitted in the interview: "I was torn between asking Kate’s dad first, and then the realisation he might actually say no came to me,"
"So I thought if I ask Kate first, then he can't really say no."
This lead to the royal disregarding the most important rule in engagement etiquette - asking the father first. However, he soon discovered that he should have had no fear as Kate's parents were ecstatic over the news.
"I managed to speak to Mike sort of soon after it happened," said Prince William.
During the interview, Kate revealed that there was some awkwardness to the situation as she could not tell her mother until her then-fiance had told her father.
“[My mother] was absolutely over the moon, and actually we had quite an awkward situation because I knew [about the engagement], and I knew that William had asked my father, but I didn’t know if my mum knew," explained Kate.
“So I came back from Scotland and my mother didn’t make it clear to me whether she knew or not, so both of us were there, sort of looking at each other, and feeling quite awkward about it.
“But it was amazing to tell her, and obviously she is very happy for us.”
Marriage historian Susan Waggoner explained that asking a father for his daughter's hand in marriage was an important part of engagement etiquette in the past because, “Historically, courtship was a family affair; a young man who caught the eye of a young woman was to arrange an introduction to the father of his chosen lady.”
These days, the gesture is seen as an act of respect towards the older generation and as a way to get closer to the new family.