It is the last word in Englishness, the soap opera to end all soap operas, everyone’s guilty pleasure. But Lord Julian Fellowes, the show’s creator, had a surprise up his aristocratic sleeve for the latest season of “Downton Abbey”: a Jewish storyline.

The fifth season of the global TV hit is due to open in the United States Jan. 4. But British viewers have already had an unexpected double whammy of Fellowes’ affection for 1920s’ ethnic minorities, since the last episodes in Season 5 not only feature Jews and anti-Semitism aplenty, but they were directed by a Jewish woman, Minkie Spiro.

Elizabeth McGovern plays Cora (née Levinson). photo/creative commons

Spiro’s background is every bit as fascinating as the fictional “Downton Abbey” she brings to the screen. Her mother, Nitza, is an Israeli educator; her father, Robin, is an ex-member of the Queen’s Royal Irish Hussars, who, after Oxford, was unexpectedly bitten by the bug of Jewish history. Together her parents went on to have seven children and to found the Spiro Ark, one of the best-known Jewish education institutes in the U.K., still going strong almost four decades later.

Minkie Spiro, herself married to an Israeli who runs a highly regarded delicatessen in north London called —What else? Minkie’s — is a diminutive 44-year-old, an erstwhile Fulbright scholar with a slew of directing experience under her belt. A nominee of BAFTA (the British Academy of Film and Television Arts), Spiro is familiar to British TV viewers for her documentaries as well as her feature material.

The award-winning “Downton Abbey,” however, is something else. A sleeper hit that has found a place in television legend on both sides of the pond, the show was barely expected to return after the first

season, let alone make it to its fifth season and apparently be cantering on through the 1920s toward the outbreak of World War II.

Its success remains something of a mystery, since much of the acting — apart from the national treasure that is Dame Maggie Smith — is simply dreadful. The plots are predictable rubbish, and storylines rise, fall and disappear without resolution.

And yet, serious and not-so-serious actors clamor to be part of the series, from Richard E. Grant, who plays a rather annoying art critic in Season 5, to a completely over-the-top Shirley MacLaine last year, playing the mother of Cora, Lady Grantham. Cora, we learned, sported Levinson as her maiden name and many were the bets that MacLaine was going to turn out to be the archetypal Jewish mamma from hell. Sadly, two Jewish parents might have proved too much for the future bride of the Earl of Grantham, but just hold on to the background of Cora’s father, as it certainly comes into play in the new season.

Minkie Spiro has become so popular with cast and crew alike that she has been chosen to direct the show’s two-hour special to be shown on Christmas Day in the U.K. As Julian Fellowes has established a bit of a reputation for killing off lead characters in that annual special, “Downton” watchers are agog to see who is due to depart.

Will a rabbi or a synagogue feature in this year’s Christmas show? Spiro is not telling, but she has said, mysteriously, that she is the perfect person to direct both the special and the opening episodes of Season 6 next year. Perhaps Carson is converting? Or Lady Edith is making a prewar visit to Mandate Palestine? Bad as it is, I can’t wait.

“Downton Abbey” Season 5, a PBS Masterpiece Classic, airs 9 p.m. Sundays, beginning Jan. 4 on KQED.