"My high opinion of Princess Diana is, if anything, only higher after all this," Cornwell told the Sunday Telegraph of her six-month investigation into the deaths. "I'm sorry I never met her, so very sorry."
Cornwell gained access to officials directly involved in the autopsy on the Princess's body and said her new material will "lay some rumors and errors to rest," the Telegraph said.
The newspaper speculated Cornwell will disprove speculation Diana was pregnant with her third child when she died in a car crash in Paris six years ago.
Cornwell will divulge her findings during ABC's "Prime Time Thursday" on Oct. 30, the Telegraph said.
The program will air before the long-awaited inquest into the Princess's death a date for which has not yet been set.
Rosie O'Donnell unveils nearly 50-pound weight loss
Putin thinks Obama would save him if he were drowning