The engagement should have been a totally happy occasion, of course, but apparently Kate had one big regret about the milestone.
In her book Kate: The Future Queen, royal expert and author Katie Nicholl explained why the joyous event was tinged with sadness for Kate.
First, some backstory: Will popped the question at Kenya’s Lake Rutundu on October 20, 2010. The couple were overjoyed, of course, but decided that they would wait a couple of weeks before making the public announcement on November 3.
During that time, they didn’t tell most of their friends and even family members, for fear of the news leaking early—this is where the regret comes in.
During the time between the engagement and the announcement, Kate’s last living grandparent, her grandfather Peter, passed away on November 2—just one day before she was planning to share the happy news with him.
“Kate was deeply saddened not to have had the chance to tell her grandfather that she was engaged to William,” Nicholl wrote, according to The Mirror. “She knew he would have been delighted for her.”
Will attended the funeral with Kate and the couple delayed the announcement as a result, ultimately telling their loved ones the good news on November 16, just hours before the news was made public.
This article originally appeared on marie claire U.S.