Prince Harry recounts driving through the tunnel where Princess Diana died in his memoir

• People released an excerpt of Prince Harry's memoir "Spare" on Thursday.
• In the excerpt, he wrote about driving through the tunnel where Princess Diana died in a car accident.

Prince Harry was searching for closure around Princess Diana's death 10 years after it happened, according to a new excerpt of his memoir published in People.

The Duke of Sussex's memoir "Spare" is set to be published on January 10. On Thursday, reports surfaced that included excerpts of the book — in which Harry opens up about his rift with Prince William — ahead of its release.

And in a new excerpt from People, Harry explores his grief over Princess Diana, reflecting on a trip he took to Paris for the 2007 Rugby World Cup when he was 23.

During the trip, Harry wrote in the excerpt published by People that he asked a driver provided to him by the World Cup to take him through the Pont de l'Alma tunnel.

Diana died in a fatal car crash in the tunnel on August 31, 1997. Harry was 12 years old at the time of her death.

According to the excerpt published by People, Harry asked the driver to go exactly 65 miles per hour, which was the speed his mother's car was going when it crashed.

"Off we went, weaving through traffic, cruising past the Ritz, where Mummy had her last meal, with her boyfriend, that August night," the prince wrote, according to People. "Then we came to the mouth of the tunnel. We zipped ahead, went over the lip at the tunnel's entrance, the bump that supposedly sent Mummy's Mercedes veering off course."

Harry went on to say he was surprised by how ordinary the tunnel was.

"I sat back. Quietly I said: 'Is that all of it? It's…nothing. Just a straight tunnel,'" he wrote. "I'd always imagined the tunnel as some treacherous passageway, inherently dangerous, but it was just a short, simple, no-frills tunnel."

"No reason anyone should ever die inside it," Harry said after going through the tunnel, according to the excerpt.

The prince went on to write he hoped the experience would bring him a sense of relief, but the opposite happened.

"I'd thought driving the tunnel would bring an end, or brief cessation, to the pain, the decade of unrelenting pain," Harry added. "Instead it brought on the start of Pain, Part Deux."