With the release of his much-anticipated memoir just one day away, Prince Harry has given multiple interviews to major news outlets ahead of publication. On Sunday, he sat down with Anderson Cooper to talk about the intimate details he shares in his book, “Spare.”

Among the many topics discussed, he writes about the death of his mother, Princess Diana, in 1997 when he was just 12 years old. He says he was unable to process his grief for several years, and, in a heartbreaking admission that makes you want to give 12-year-old Harry a hug, he says he held out hope that his mother was alive—well into adulthood.

“For a long time, I just refused to accept that she was—she was gone,” Harry said. “Part of, you know, she would never do this to us, but also part of, maybe this is all part of a plan.”

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“You really believed,” Cooper asked, “that maybe she had just decided to disappear for a time?”

“For a time, and then that she would call us and that we would go and join her, yeah,” said Harry, who was 12 when his mother died.

“How long did you believe that?” Cooper asked.

“Years. Many, many years,” Harry said. “And William and I talked about it as well. He had—he had similar thoughts.”

“You write in the book,” Cooper said, “‘I’d often say it to myself first thing in the morning, ‘Maybe this is the day. Maybe this is the day that she’s gonna reappear.””

“Yeah, hope. I had huge amounts of hope,” Harry said.

It wasn’t until he was in his early twenties that he began to accept that his mother was really gone—after he asked to see the police report about his mother’s Paris car crash. He said he requested to read through it and look through the photographs so he could know for sure what happened.

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“Mainly proof,” Harry said when Cooper asked why he wanted to look. “Proof that she was in the car. Proof that she was injured. And proof that the very paparazzi that chased her into the tunnel were the ones that were taking photographs—photographs of her lying half dead on the back seat of the car.”

His private secretary at the time prevented him from seeing the more gruesome photos of Princess Diana in the wreck, thankfully. When he was 23, he actually visited Paris himself and asked his driver to drive through the tunnel where his mother was killed.

“I wanted to see,” Harry said. “I wanted to see whether it was possible driving at the speed that Henri Paul was driving that you could lose control of a car and plow into a pillar killing almost everybody in that car. I need to take this journey. I need to ride the same route where—”

“The same tunnel, the same speed, your mother was going,” Cooper said.

“All of it,” Harry said. “Yup. Because William and I had already been told, ‘The event was like a bicycle chain. If you remove one of those chains, the end result would not have happened.’ And the paparazzi chasing was part of that. But yet, everybody got away with it.”

Though in the official report, the deaths of Princess Diana, her boyfriend Dodi Al-Fayed, and their driver Henri Paul was ruled an “accident,” Prince Harry and Prince William considered re-opening the inquest about the crash at one point in order to get the answers they truly needed.

When asked if he has the answers he’s been looking for in relation to Princess Diana’s death, he said no.

“Truth be known, no. I don’t think I do,” Harry said. “And I don’t think my brother does either. I don’t think the world does. Do I need any more than I already know? No. I don’t think it would change much.”