Indeed with its large, eclectic cast, Belgravia isn't too different to Downton Abbey, which for six years, until its conclusion last Christmas, drew viewers into the lives of those living both upstairs and downstairs in the Crawley family's fictional Yorkshire estate.
"You get involved with the characters emotionally, and you come to like them," says Fellowes. "In some cases, fans come to believe in them to a slightly alarming degree, as to some of them they really are like real people and there are moments when you have to say 'calm down!' But I love that feeling that you've really got people involved and really empathising with these characters."
From the sexual assault of Anna Bates to Lady Sybil's sudden death in childbirth, Lord Fellowes received some moving responses from viewers to certain storylines in Downton Abbey.
"I had letters that really made me cry," he recalls. "It's very rewarding when that happens as you feel like you've helped someone work through something in their own lives. I like that ongoing relationship in television, and I hope I'm going to like it in this form as well."
Starting out by turning out "train-reading trash" -- referring to the romantic novels he penned under the pseudonym Rebecca Greville in the 1970s -- Fellowes claims he isn't "a complete stranger" to novels.
But since penning the more respectable, bestselling Snobs in 2004 and then Past Imperfect in 2008, he has exclusively devoted himself to small and big screen projects such as Downton Abbey and his upcoming NBC series, The Gilded Age. Due to start production later this year, it is set in 1880s New York and is described as "a sweeping fictional epic of the millionaire titans of New York City".
Fellowes acknowledges it has been a while since he wrote a book, but admits he is once again enjoying the relative autonomy of prose.
"When you're doing a book, it's just you and your editor, and you're just trying to get a finished product that you're both happy with.
With film and television, there's a whole committee and each time you think you've finished one stage, it goes on to the next stage and there's another committee there as well. So you're dealing with all these different people who are all putting in their 10 cents worth. In a way, writing a book is a much cleaner process and it's easier to maintain your voice, so I'm rather enjoying writing books again."
Belgravia opens in Brussels on the eve of the Battle of Waterloo in the summer of 1815 and advances to 1841. His publisher, Orion, suggested Fellowes should focus the origins of the exclusive West London suburb, Belgravia.
"They said that I should start out with the Duchess of Richmond's Ball, which is so iconic, as it's one of the 10 most famous parties that has ever been given," he says, referring to the lavish soiree that was held the night before the Battle of Quatre Bras.
"There's something about the tragedy in which it ended with all these young men running off, many of them to be killed. It's very much a truthful account of what happened with the messenger arriving from the Prince of Orange, and the fact that while the soldiers were running for their headquarters, some couples were still dancing, which is extraordinary to think of."
Noting in the first chapter that, "the past is like a foreign country," Fellowes believes we are fascinated by the idea of a strictly ordered society because it was so different to the more carefree way we currently live.
"We eat when we're hungry and we wear the clothes that we feel comfortable in," he says. "We don't really allow much ritual into our lives compared to what it was like 200 years ago when ritual dominated every single waking minute, and for all the classes actually.
But despite its many more rules and regulations, Fellowes insists 19th-century life wasn't completely unrecognisable to how we think and behave in this day and age.
"Within those orders, most of the emotions are exactly the same as they are now," he says. "People still wanted to get on, and they wanted to be happy with their marriages. But they had less open choice than there is nowadays as they had to marry the people their family approved of and they couldn't just marry for love in a random way like we do. I like those contrasting emotions and people can identify with that even if the customs seem a million miles away."
Revealing that "is why I find female characters very interesting when you're writing about the past," Fellowes acknowledges that women were considerably more restricted in how they could go about their daily existence.
"You always had this tension between their potential and what was possible for them to achieve," he says. "Some of them went on to become very successful painters or novelists, but a hell of a lot just ended up banging their heads against a brick wall to try and make a life that was worth living. All of that is petrol to a writer, and it's why, as in Downton, we have women trying to get what they want by pushing against the constraints that surround them, and one of them has to go to extremes to rescue her life."
Belgravia
(Orion $38)
