Rev actor Tom Hollander stars in the title role of the adaptation of Anthony Trollope's novel.
One of Fellowes' favourite books, it is set in the village of Greshamsbury in the fictional county of Barsetshire.
The adaptation depicts the life of Doctor Thorne, who lives with his penniless young niece Mary, played by Rada-trained newcomer Stefanie Martini.
Mary is devastated when she learns she is the illegitimate child of the doctor's late brother.Her predicament is made worse by the love between her and Frank Gresham (newcomer Harry Richardson), the heir to the Greshamsbury Estate.
Frank's overbearing mother Lady Arabella (War And Peace's Rebecca Front) insists he must save the family from financial ruin by marrying wealthy American heiress, Miss Dunstable (Mad Men actress Alison Brie).Meanwhile, Doctor Thorne acts as both physician and adviser to millionaire Sir Roger Scatcherd (Lovejoy's Ian McShane), who has the fate of Greshamsbury in his hands.
Like Downton, the three-part production, which will also feature Prince Harry's former girlfriend Cressida Bonas as Mary's confidante Patience Oriel, is another period drama.Fellowes spoke with enthusiasm about its comical qualities.
"There is wonderful comedy in Doctor Thorne - the snobbish Countess De Courcy, the duped fool Augusta Gresham, the angry, awkward Mr Moffat, the waspish Lady Alexandrina, the archetypal smoothie Mr Gazebee - but there is generosity too," he told.
Trollope, a prolific writer of the Victorian era, is often compared with contemporary Charles Dickens, but Fellowes appeared to appreciate aspects of the former's writing more.
"All Dickens' heroines are whiter than white, his villains blacker than black, something Trollope entirely avoided," he told the Radio Times.
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"In short, what enrages his enemies, then or now, is the popularity of his productions and the enduring audience that his work still reaches, a century and a half later."
This is the first television adaptation of Doctor Thorne, and Fellowes hopes it will persuade viewers to read more books by the London-born author.
"I even took Is He Popenjoy? on honeymoon and sat with my nose in it for far more of the time than my wife appreciated," he said.
- AAP
