"Downton Abbey" season 5 has been slotted to premiere in the U.S. in 2015 with which its new episodes will be centered on several changes as Britain welcomes its first Labor party government and the Crawley estate is faced with intense social changes.

Many of the original cast members will be reprising their roles, including Maggie Smith as the Dowager Countess, Hugh Bonneville as Lord Robert Crawley, Michelle Dockery as Lady Mary, Jim Carter as Mr. Carson and Laura Carmichael as Lady Edith.

The upcoming season's guest stars will include "Four Weddings and a Funeral" actress Anna Chancellor who will portray Lady Anstruther, alongside Russian actor Rade Sherbedgia who will play a refugee who escaped the Russian revolution following World War I.

"Withnail and I" actor Richard E. Grant will be playing Simon Bricker as a guest of the Granthams at Downton Abbey.

As reported by The Telegraph, Elizabeth McGovern (Lady Cora Crawley) stated that some of the characters will find it difficult to address the challenges that have been brought upon Downton.

"Some of them struggle with it more than others," McGovern said. "I think that it's sort of a rift or a source of tension in the marriage that Robert finds it so much more difficult to adjust than Cora does."

Bonneville has also opened up about keeping relationships "fresh", particularly his character's marriage with Cora.

"In the opening episode we discover it's their 34th wedding anniversary and, well let's put it this way, there's a chance, I think, for someone who has been married that long -- there can be certain things taken for granted, and therefore when couples have got stuck in a rut, you need to keep things fresh," Bonneville said. "And over the horizon comes forces that challenge the solidity of their marriage."

Dockery' s character, Lady Mary, will finally be moving on from the passing of her husband, Matthew.

Daily Mail has reported about the fifth season exploring the homosexuality of Thomas Barrow, who is being portrayed by Robert James-Collier. To this, the 37-year-old actor said that his character seeks to "change" his sexuality as the season unfolds.

"Downton Abbey" season five will air on PBS on Jan. 4, 2015.