Advertisement'Downton' Returns With Aristocratic Class And ClashJanuary 03, 2013David BiancullifacebookEmailSocial changes, romantic intrigues and financial crises grip the English country estate in the third season of Downton Abbey, starting Sunday on PBS. Shirley MacLaine joins the cast as Cora's wealthy American mother, Martha Levinson. (Carnival Film & Television Limited 2012 for Masterpiece)