Season 4 of the popular show is airing in the United Kingdom months ahead of its planned U.S. broadcast.
Britain's ITV network received 60 complaints and fans voiced their outrage on Twitter after beloved "Downton" housemaid Anna May Bates, played by Joanne Froggatt, was raped off-camera by a guest's valet in Sunday's episode.
"The whole point of the way we do things on 'Downton' is we don't do them gratuitously," Fellowes told the BBC.
"We are interested in exploring the resultant emotions and the effect these things have on people," he said. "If we'd wanted a sensational rape we could have stayed down in the kitchen with the camera during the whole thing and wrung it out. The point of our handling is not that we're interested in sensationalizing, but we're interested in exploring the mental damage and the emotional damage."
"I think it's a really brave thing to do ... I believe that Julian has written it in a way that is not gratuitous at all," Froggatt told the BBC. "We all felt a big responsibility to get it right."
The early 20th century-set series is about a wealthy family and the people who work for them at their country estate.