Downton Abbey creator Julian Fellowes has cast two titans of the industry in his upcoming HBO drama The Gilded Age. Christine Baranski and Cynthia Nixon are set to play sisters, Deadline reports. Amanda Peet and Morgan Spector will also star.

The Gilded Age, which was originally ordered at NBC before moving to HBO earlier this year, follows New York City millionaires in the 1880s. Baranski has been cast as Agnes van Rhijn, a stubborn aristocrat who refuses to accept that the world has changed. The role will not interfere with Baranski's work on The Good Fight.

Nixon will play Agnes's sister, Ada Brook, who is described as "not naturally confrontational, but ... capable of standing up for what she believes." Ada never found a way out of the Old South as it collapsed and was forced back on her sister's charity.

Peet, meanwhile, will play Bertha Russell, a middle-class woman who has come into new wealth thanks to the financial genius of her robber baron husband, George (Spector) — a man who makes "pleasant enough" company but is ruthless in business.

The Gilded Age tells the story of Marian Brook, the orphaned daughter of a Southern general, who moves into the home of her rigidly conventional aunts in New York City. Accompanied by the mysterious Peggy Scott, an African-American woman masquerading as her maid, Marian gets caught up in the dazzling lives of her stupendously rich neighbors, led by a ruthless railroad tycoon and his ambitious wife struggling for acceptance by the Astor and Vanderbilt set. Will Marian follow the established rules of society, or forge her own path in this exciting new world that is on the brink of transformation into the modern age?

Created, written and executive produced by Fellowes, The Gilded Age reunites the Downton creator with producer Gareth Neame and director Michael Engler.

<p>Christine Baranski, Cynthia Nixon </p>

Christine Baranski, Cynthia Nixon