Their engagement was announced around eight years ago and Catherine revealed in a video interview with ODN that she was completely "shocked" when William asked for her hand in marriage.
Prince William and Kate Middleton: He travelled to Africa to be with her
A then twenty-eight-year-old Kate happily admires her engagement ring while William's confessed, "As every guy out there will know, it takes a certain amount of motivation to get yourself going. So I was planning it and then it just felt really right out in Africa. It was beautiful.”
Will and Kate had already discussed getting married
Even though they had already discussed getting married, when Will got down on one knee it was still "a total shock when it came" according to Kate. William actually proposed Kate while they were on a trip with friends in Kenya, as William's love for Africa meant that he felt it was the perfect place to ask Kate, whom he had been in a relationship with for nine years at that point, to marry him. Kate described the moment as "very romantic".