On what should have been the happiest day of his life, Prince William was plagued by memories of the saddest: the day his mother, Princess Diana, was killed in a car crash in August 1997.
"I sort of prepared myself beforehand so that I was mentally prepared," William says of his April 29, 2011 wedding day. "I didn't want any wobbly lips or anything going on. It's the one time since she's died where I've thought to myself, 'It would be fantastic if she was here,' and just how sad really for her, more than anything, not being able to see it."
William continued: "I think she would have loved the day, and I think, hopefully, she'd be very proud. I'm just very sad that she's never going to get a chance to meet Kate [Middleton]."
"I think she had the best seat in the house, probably," Harry says. "But yeah, she would have loved to have been there."
The Jubilee Queen With Katie Couric airs Tuesday at 9 p.m. EST on ABC.
Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!