Season three of Downton Abbey premieres on PBS this Sunday (January 6, 2013), with the arrival of silver-screen icon Shirley Maclaine. The Oscar and Golden Globe winning actress plays Martha Levinson in the best-loved period drama, and is set to go head-to-head with the stoic Countess of Grantham, played by Maggie Smith.

MacLaine - perhaps best known for The Apartment and Terms of Endearment - explained to the New York Times how she prepared to act alongside Smith. "I thought the best course of action in going toe-to-toe with Maggie would be a sense of American expressive feeling," she explained. In one upcoming scene, MacLaine's character serenades Smith, "I told her I was going to sing it, and first she said to me, [genteel Maggie Smith voice] 'You know, dear, when you do that, I'm going to fall off the chair.' I said, 'OK.' And then she said, 'No, I think not. I think I'll fall asleep.' I said, 'OK, that's good, too.' And then she said, 'No, I think I will cry.' I said, I don't know what you'd do that for, but whatever. What she did instead was flirt back. [Laughs] I was so surprised." 

Legendary actress MacLaine was married to businessman Steve Parker until 1982, though revealed to Oprah Winfrey in 2011 that she had an open relationship with her husband. Smith has been married on two occasions, to actor Robert Stephens and playwright Beverly Cross, and she and MacLaine compared notes on past lovers on the Downton Set. "We sat and we reminisced about life and lovers and the business and directors," said MacLaine, adding, "That was really interesting and so much fun.When we were doing a press conference here, someone asked me if I had known Maggie before. And I said, 'Oh, yes, we were lovers in another life.' [Laughs] I don't know where that came from."