In a raw, honest, and poignant series on ITV and HBO’s Our Mother Diana: Her Life and Legacy special, Prince Harry and Prince William share never-before-seen photographs of their late mother Princess Diana, and open up about their life together.

August 31 marks the 20th anniversary of her death in a Paris car crash, and the special airs tomorrow, July 24 — be sure to tune in!

Diana’s brother Charles Spencer, Elton John, and Rihanna all make an appearance.

The princes are definitely following in their mom’s footsteps, especially when it comes to HIV education and outreach. At one moment, Harry discusses the last conversation he ever had with Diana was very short: “And if I’d known that that was the last time I was going to speak to my mother the things that I would – the things I would have said to her,” Harry said.

“It’s one thing doing a documentary like this and it’s another thing standing front of all of you guys and explaining about something very personal to you,” William said. “Nevertheless, I think it’s very important that I’m here to do that.”

He added, “We feel hopefully this film will provide the other side from her close family friends that you might not have heard from before, from those who knew her best, and from those who want to protect her memory and want to remind people of the person that she was: The warmth, the humor, and what she was like as a mother, which probably hasn’t come across before in many other pieces from other people.”

Harry added “There’s not a day that William and I don’t wish that she was still around, and we wonder what kind of a mother she would be now, and what kind of a public role she would have, and what a difference she would be making.”