The most awaited new season of U.K.'s upstairs-downstairs drama "Downtown Abbey" is finally here in the U.S. and fans are hankering for more details on what to expect when the series progresses.

Series creator Julian Fellowes dished on the challenges the "Downtown Abbey" crew has to face in making its fifth season.

"The challenge of anything is to keep it interesting," Fellowes told The Hollywood Reporter. "Do we care? Does it matter whether Mary is happy or unhappy? Does it matter whether Edith looks after her child or doesn't? And really, what it comes down to: Are these still people with whom the audience wants to be involved? I think that's the challenge at the start of the series, and it's the challenge at the end of it."

Fellowes went on to discuss the new theme of the series which, as found out, would be more about the characters now living in a new era.

"I think the theme of the fifth series is that the changing world has finally made it over the park wall and is encroaching on the house, and they are all, in different ways finding that they're living in 20th century instead of the 19th," Fellowes said.