NEW YORK — Secrets of “Downton Abbey” stars revealed!

Carson swears! Branson bolts Boston! Mrs. Hughes rocks sequined sneaks! Lord Grantham confesses to killing the hound! Dinner scenes detested! Molesley, footman of a thousand mopes and sighs, smiles!

Abbeyites, it’s beginning to look a lot like Downton. The sixth and final season of the PBS “Masterpiece” juggernaut debuts Sunday to remedy post-holiday doldrums and agitate any latent Anglophilia that the 300th broadcast of “Love Actually” failed to excite.

A passel of “Downton” stars flew stateside to launch the beginning of the end of Masterpiece’swildly popular series, averaging almost 13 million besotted fans each week. The manor’s newest sweethearts, Jim Carter (Carson the butler, blessed with owl-like eyebrows) and Phyllis Logan (housekeeper Mrs. Hughes) shared coffee at midtown Manhattan’s swank Lambs Club restaurant.

In the Season 5 finale, which aired last March, Hughes accepted Carson’s proposal with the immortal words, “Of course, I’ll marry you, you old booby. I thought you’d never ask.”

The old booby believes that this was his doing.

Series creator “Julian Fellowes would probably deny this, but I wrote a note to him at the end of Series One saying, ‘You do know Carson and Hughes are going to have to get married,’ ” says Carter, 67. (In real life, he is married to Imelda Staunton, who played pink-suited Harry Potter tyrant Dolores Jane Umbridge.)

The romance “seemed quite evident early on, but it eked out at the pace of a glacier. Nice that downstairs got to have a love affair, especially an older pair,” says Logan, 59. “Unlike American shows, where every character is told what their arc is, we are told nothing. We only know it when our script comes through the post. We’re kept in the dark like mushrooms and fed …”

Logan starts to utter a very un-Hughesian term for fertilizer but stops herself. (Carter does not when dissing a rude fan.)

Fetching and sparkling down to her slip-on shoes, the Scottish actress says, “I think I would kill myself if I went about looking like Mrs. Hughes.” She dons a dour wig for the role, little makeup and, during the initial season, one vintage dress that disintegrated from constant wear. “I’ve had my day of being the young ingenue, the romantic young lead or whatever,” she says. “I’m a character actress nowadays. Bring it on, say I.”

The pair are adored sweethearts in Britain, their fan base dubbed “Chelsies” for Charles (Carson’s rarely spoken first name) and Elsie (Hughes).

Though their characters are proper and reserved, the actors have no trouble dissing or sharing. Many of them tired, as did viewers, of the perpetual misfortunes of the original star-crossed downstairs lovers, Anna and Bates. He’s in prison. She’s in prison. Now … oh, who cares?

To a person, the cast loathed the dinner scenes – hot lights, shuttered windows, stinking fish, endless closeups and reaction shots, three days to shoot three pages of script to create three minutes of finished film.

“I will not miss them. They’re horrendous,” says Allen Leech, 34, who plays Branson, the Irish former chauffeur who decamped to Boston but – spoiler alert! – returns this season to “Downton.”

Over a beer, Leech reveals that Matthew – rest in peace, dear Matthew – was supposed to marry Sybil – ditto, sylph-like Sybil – who instead married his character and brought him upstairs to live a life of tweeds and dinner jackets. Then she died of eclampsia after the birth of their child.

“I had no idea I would marry her. I was literally hired to just come and drive Maggie Smith around,” Leech says. During the first season, he almost hit the entire crew before performing a hand-brake turn in a 1910 Renault worth $750,000.

As for the unfortunately named yellow lab, Isis (after the Egyptian goddess), Hugh Bonneville, 52, who plays Lord Grantham, confesses, “I suggested killing off the dog. I was very fond of the dog, but in story terms, it was really quite old.” The series begins in 1912 and finishes in 1925.

Plus, it allowed Grantham to openly grieve in the way that only a British aristo can for a noble hound and not, for instance, for one daughter marrying the help or another having a child out of wedlock.

Elizabeth McGovern, 54, the principal cast’s lone American, plays his wife, which permitted her to wear beautiful togs but do little else. “I would often feel, over the course of the years, this feeling of being strangled. I didn’t have a voice as Cora,” says the actress, whose first professional role was in the 1980 film “Ordinary People.” “Nothing she said really mattered to anyone. She wasn’t in control of her own destiny.”

Lady Grantham never speaks bluntly, like her mother-in-law or eldest daughter, Mary. McGovern’s release from such propriety was her rock band, Sadie and the Hotheads, “a real tonic. My personal way of escaping.”

In Britain, most series run three years and, like “Downton,” for nine episodes each season. Six years is rare. Over time, long-running television shows tend to smooth rough edges, create romance where little smolders, and transform sworn adversaries into eternal besties.

“Downton” is no exception. Mrs. Crawley and the Dowager Countess, who exchanged zingers over class and manners, became friends. (Though nothing has stopped the countess, played by the formidable Smith, from delivering such priceless quips as “What is a weekend?” and “I have plenty of friends I don’t like.” )

Even Thomas Barrow – nasty, duplicitous, blackmailing Thomas – did good turns last season. What’s next? Squabbling sisters Lady Mary and Lady Edith growing to like one another?

Kevin Doyle grows philosophical discussing his role as poor, put-upon Molesley. The character was initially written to appear in only a few episodes as butler to Matthew and Isobel Crawley.

“Not everyone can be happy,” says Doyle, 55. “There’s this fascination that people have for happy endings all the time. It doesn’t always work out.” He arrived at the restaurant with takeout fruit salad, which seems so Molesley. (Bonneville feasted on pasta with crab.)

“Molesley and his parents knew that he had a brain. He wanted to use it, teach or something like that but, because of family circumstances, he couldn’t,” the actor says. Molesley is his first servant.

“I play a lot of dark characters,” says Doyle, who seems charming and sunny. “I’m normally cast as serial killers.”

Does Molesley learn to stop moping and have a happy ending? His story is “really lovely,” Doyle says, with an alluring smile. “It isn’t what you expect. It was grand. I’m really pleased with him.”

The series occupied the cast’s lives for six months of every one of the last six years, unlike anything they’d experienced before. But the actors appear relieved to be free from period costumes and three-day dinner scenes.

“I’m incredibly grateful that it’s brought so much pleasure. And I’m quietly pleased that it’s come in sort of the autumn of my career, rather than early on,” Carter says. “The kids, if it’s the biggest thing they do, it could be a bit disorienting.”

Logan, his on-screen sweetheart and off-screen chum, laughs, “Oh, yes, it could be all downhill from here.”