Princess Diana could have survived fatal Paris crash if she made one simple choice, investigator says

One small decision before Princess Diana’s 1997 crash could have saved her life and changed history.

On Aug.

31, 1997, Diana, Princess of Wales, was killed alongside her companion, Dodi Fayed, and their driver, Henri Paul, when their Mercedes crashed at high speed in a Paris tunnel while paparazzi pursued them.

The mother of two was just 36.

The tragedy is getting a fresh examination in FOX’s new special, "Celebrity Crime Scene: Princess Diana," which airs Aug.

20.

Using modern recreation technology to reconstruct the events surrounding the crash, host and investigative crime journalist Jakson Buhaj joins British forensic psychologist Kerry Daynes and former U.S.

Secret Service agent Rich Staropoli to revisit the evidence, scrutinize the theories and explore what really happened that night in Paris.

INSIDE PRINCESS DIANA AND JFK JR'S SECRET MEETING THAT FUELED ROMANCE RUMORS FOR DECADES Buhaj told Fox News Digital that knowing one simple thing might have saved the princess makes her death all the more haunting.

"It's very odd that no one was wearing a seat belt," he said.

"You would think that [Dodi Fayed's bodyguard] Trevor Rees-Jones, who was sitting in the front seat directly ahead of Diana ... would caution her that she should definitely put a seat belt on, considering the car is driving way over the speed limit. ...

Yet no one thinks to do that." Rees-Jones accompanied Diana and Fayed on their final trip, but he worked as a bodyguard for Fayed's family, not as Diana's official protection officer.

WATCH: PRINCESS DIANA'S FINAL MOMENTS: WHAT COULD HAVE SAVED HER? "What I think is the most tragic thing about this is that had everyone been wearing their seat belt, unfortunately, Henri Paul and Dodi Fayed probably would’ve passed away, but Diana most likely still would’ve been with us," Buhaj said.

"And I think that’s something that really stuck with me after we wrapped filming, that there is a whole other timeline out there where a seat belt could have saved Princess Diana." For years, one detail about the crash was widely repeated: Rees-Jones survived because he was the only person in the Mercedes wearing a seat belt.