The gown sparked such intense interest that young designers David and Elizabeth Emanuel locked the ivory silk dress, which had a 25-foot (7.6-metre) long train, in a safe at night.
The Daily Telegraph suggested the report's findings could be comparable to phone-hacking revelations at the News of the World tabloid, which forced its closure.
The 72-year-old Prince of Wales, who tested positive for coronavirus last year and suffered mild symptoms, had his first dose of a vaccine in February.
"It was like having an out-of-body experience ... I think we were both really aware, even in advance of that, this wasn't our day, this was the day that was planned for the world."
They have moved with their son Archie to Southern California to live a more independent life and escape the British media, and next month will give a "wide-ranging" interview to US chat show host Oprah Winfrey.