"All I want to do is try and fill the holes my mother has left," Prince Harry, 32, says in a new clip. "And between myself and William, and everybody else that's in those privileged positions, to try and make a difference. And that's what it's about for us, trying to make a difference."
The two-hour documentary will explore the tumultuous week following the death of Princess Diana on Aug. 30, 1997, after she was involved in a fatal car crash as French paparazzi followed her through Paris.
For Prince William, the 35-year-old royal and father of two explains how both of his parents brought him and Harry up to understand that "there is this element of duty and responsibility that you have to do things you don’t want to do." However, it became harder once their mother died.
"When it becomes that personal, walking behind your mother’s funeral cortege, it goes to another level of duty," William adds. "But I just kept thinking about what she would want and that she’d be proud of Harry and I. And effectively, she was there with us. It felt like she was walking alongside us to get us through it."