The 1912 tragedy has been adapted many times, most famously as 1958's A Night To Remember and James Cameron's 1997 Oscar winner Titanic, but the Downton Abbey creator insisted that his show would have a fresh slant on the events of the ship.
Speaking at the miniseries launch in London yesterday, producer Nigel Stafford-Clark said: "We took the decision right at the start that we were making a very different version of the Titanic story and therefore while we were extremely grateful to Cameron for developing the technology that enabled us to do it, we weren't going to parallel ours to his."
Fellowes said: "This is a portrait of a ship in a way that other versions haven't been. Right from the start we set out to tell the story of the whole ship. It's a great tragedy, obviously, but I was thrilled by the idea of having a chance to shape another version of it."
The self-confessed Titanorak continued: "There are certain disasters that seem to latch on to our psyche. The Titanic is the perfect disaster - it has everything in a compact form. There are rich aristocrats, movie stars, bankers. In steerage, there are all of these desperate people heading for new lives. They took their whole families and they were wiped out.
"It is all tragic. You almost can't bear to think about it. They weren't tragic people, they were people who got caught up in a tragedy. I find that very moving."
Stafford-Clark confirmed that the series would feature a mix of real and fictional characters, adding that he and Fellowes didn't decide on which fictional parts should survive until they reached the end of the third episode.
"We duly got together when we got to that point, only to find that we didn't want anyone to die," he said. "It took quite a long time for us to work it out."
The four-part miniseries will air in April to mark the landmark 100th anniversary of the ship's sinking. It will be shown on ABC in the US.
> 'Downton Abbey' creator Julian Fellowes 'Titanic' trailer pictures
> Linus Roaches leads ITV 'Titanic' cast
See pictures from the series below: