The wait is nearly over. Masterpiece’s vaunted drama "Downton Abbey" returns Jan. 6 for its third season, with the Crawleys facing financial ruin and an acting legend joining the cast.

The PBS series about an aristocratic British family and their upstairs/downstairs intrigue is a global phenomenon -- not to mention the most-watched Masterpiece show on record. 

And now with three seasons under their rather constricting belts, the cast, including Rob James-Collier who plays Thomas, can relax a bit.

“I’m talking to you in Boston about our little British show -- it’s like mind boggling,” James-Collier said. “Well, brilliant. We never thought, no one ever envisioned this happening, but it has, so I’m just rolling with it and enjoying it.”

Season three debuts on Sunday night with the Crawleys treading into a new age. It’s 1920 and post-World War I Great Britain means quickly changing politics, social mores and sensibilities. And most disastrously for Lord Grantham, played by Hugh Bonneville, it also means possible financial ruin.

“He becomes a little bit of a dinosaur in that he wants things to go back to 1912, to the pre-war certainties, to the pre-war values,” Bonneville said. “And of course that’s not going to happen. Added to which, we discover, that Robert has made a catastrophic financial investment. Which means that the estate is going to have to be sold. So he has failed.”

Masterpiece Executive Producer Rebecca Eaton says the show remains entirely Julian Fellowes creation – he’s written all of the series himself.

“If you think about it, it’s almost like a mathematical equation of who’s in jeopardy with whom and who needs who to accomplish something.”

This season introduces us to a spirited and brash American — Lady Grantham’s mother -- played by Shirley MacLaine. 

“No other actress was approached,” Eaton said. “It was sort of a perfect fit because it needed to be an American actress who could hold her own with Maggie.  And Shirley is – she’s been everything, as Maggie has done comedy and serious drama, and she is quintessentially American.”

The two seasoned actress got along “fabulously,” James-Collier said.

“I remember there was a scene in a church, where they were on the pew and I was just watching them, and they were just in between takes laughing and I thought, the stories they must be telling each other, you know, it’s a who’s who, who they’ve worked with,” he said. “They’re probably like, What’re we doing here with this lot?”

The “lot,” by the way, happens to be a pretty self-effacing bunch—bewildered by their success and enjoying their moment. Bonneville shook off the idea of discord between the actors downstairs versus the actors upstairs.

“I always tease that Daisy the kitchen maid is the most demanding bitch off-camera,” Bonneville said. “We’re very egalitarian bunch.”

Bonneville said the highlight of the show’s popularity was getting courtside tickets to a Knicks game.

“I’ve never been to a basketball game and to go to the Knicks game and to have courtside seats because of our little telly show, it’s a nice perk,” he said.

“Courtside,” James-Collier added. “I’d never picked a team. But now I’m a Knicks fan.”

James-Collier said Downton winning a Golden Globe last year also stuck out.

“That’s Hollywood, that’s the heart of Hollywood,” he said. “And you’re in a room surrounded by, you know, the royal family of movies and television, and to have Downton recognized there was fantastic.”

So far, the momentum only builds.

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