He's penned the most successful period drama to grace our TV screens in years, but now Downton Abbey creator Julian Fellowes is leaving fiction behind and delving into the true stories behind Britain's great houses.
"It is no secret that I am fascinated by the lives of those who lived inside these houses, the variety of type, the range of activities, the customs and limitations that forced men and women to shape their ambitions," says the man who breathed life into the quick-tongued Dowager Countess and the rest of the Crawley clan. "I couldn't wait to learn the truth about what really went on behind those great panelled doors."
So where will he be heading to discover what happened to the real Lady Marys and Mrs Patmores?
The two-part documentary will see Fellowes visit the grand Burghley House in Cambridgeshire and Goodwood House in West Sussex. Alan Brown, the show's executive producer, says: "We wanted places that had 'big moments in history' associated with them, great stories about the people that owned them, but in particular where there were interesting leads on servant stories."
And there's no denying that Fellowes found what he was looking for. From a cook murdered by his employer to scandalous marriages and a disgraced dairy maid, Burghley and Goodwood had plenty of their own stories to tell.
While Fellowes is no stranger to a little drama - in the history of Downton we've had deceased bedfellows, cross-class romance and imprisoned valets - even he says some of his discoveries were a "real and shocking revelation".
In particular, there was the discovery of a black servant working at Goodwood in the 1770s. "Were they slaves or not?" asks Fellowes. "If they were free, how free were they?" And what about the murder of Thomas Brinknell, a cook at Burghley House? "The savagery with which the truth about the incident was twisted revealed Burghley's ruthlessness," reveals Fellowes. "His singularity of purpose, no matter who was hurt in the process, was terrifying, even at this distance."
After a Downton Christmas special that left many fans disappointed, perhaps these shocking historical discoveries will give Fellowes the inspiration he needs to win back his dedicated followers in series four...
Great Houses with Julian Fellowes is coming to ITV1 soon