Speaking to The Daily Telegraph, Newton reveals that researchers on an upcoming season of SBS' Who Do You Think You Are? discovered a horrifying piece of family history.
The show traces the ancestry of celebrities and returns next month, where Patti's episode will air.
The wife of TV legend Bert Newton told The Telegraph that the distressing discovery came when looking in to her father's paternal family tree.
'Every time someone would mention the series before I did it, they'd say 'I wonder what they'll find?' And I'd say, 'Oh, they'll probably find a murderer and I'll die'. And they did', she told the newspaper.
On Patti's paternal line, the death of an infant baby several generations back sparked a media frenzy and subsequent criminal trial.
The Aussie star knew nothing of this shocking lineage, and the discovery led her to break down in tears.
'I had no idea it would be so dramatic,' she told The Telegraph, as she reportedly 'dissolved into tears.'
The show returns to air on SBS April 17.