Bad news, fans who‘ve gotten religious about “Downton Abbey“: Lady Cora Crawley is not — I repeat, not — Jewish.

Although this may be of absolutely no consequence to most people, for at least some admirers of the hit TV series, it’s a real disappointment. (Before anyone accuses me of revealing spoilers, rest assured that Judaism does not play a part in the British show’s third season, which premieres in the US Sunday on PBS.)

With the approach of new episodes, some fans may be wondering about the religious background of the series’ female lead, an early 20th-century heiress living on the English estate of the title.

Viewers’ curiosity about the American-born Lady Cora — also known as the Countess of Grantham — stems from an official online biography posted online last year, in which the character is described as “the beautiful daughter of Isidore Levinson, a dry goods multimillionaire from Cincinnati.”

With the revelation of that telltale maiden name, some of the series’ Jewish fans immediately began speculating about how her heretofore unrevealed identity might play out in Season 3.

Their interest was only heightened by news that Shirley MacLaine had agreed to join the show as Lady Cora’s mother, Martha Levinson. Who could contain her excitement at the prospect of a Jewish mother arriving from America to shake up stodgy Downton Abbey? Best of all, would she spar with Lady Cora’s mother-in-law (Maggie Smith), the fantastically barb-tongued Dowager Countess?

Alas, all hopes have been dashed. As impatient as viewers may be for the new season, they will not see the cook, Mrs. Patmore, bake challah; the butler, Mr. Carson, serve Shabbat dinner; Lady Cora bless the candles; or her eldest daughter, Lady Mary, wear an exquisite Star of David necklace.

‘The wonderful thing about the British aristocracy was that they were both incredible snobs and very realistic. A Jew was no more vulgar to them than an American’

The reason neither Martha Levinson nor Lady Cora (played by Elizabeth McGovern) are Jewish, it turns out, is very simple: They’re Episcopalian.

We know this because the definitive guide to Season 3, Jessica Fellowes and Matthew Sturgis’ “The Chronicles of Downton Abbey,” tells us so. (They should know: She’s the niece of Julian Fellowes, the show’s creator.)

An attractive coffee-table book, the tome contains a chapter devoted to “Mrs. Isidore Levinson,” which states that although, “Martha’s husband was Jewish, she herself is not, and their children were raised Episcopalians.”

Well, you could have fooled me, since I thought MacLaine played Martha as Jewish. (A diehard fan, I’ve seen the third season, which has already aired outside the US.)

With Martha Levinson’s brash demeanor and over-the-top wardrobe, I thought producers were signaling not merely that the character is nouveau riche, but that she’s nouveau riche and Jewish. That interpretation is backed up by “A Perfect Fit: Clothes, Character and the Promise of America,” in which historian Jenna Weissman Joselit reports that rich American Jewish women in the early 20th century shared a predilection for overdone outfits, gaudy jewelry and garish accessories.

Peter Stansky, a professor of British history at Stanford University, was equally fooled. He caught parts of the show’s third season as it aired in England during a visit in the fall.

"Abbey" enthusiasts see potential for conflict between the sharp-tongued Dowager Countess (Maggie Smith, right) and her nouveau-riche American in-law, Martha Levinson (Shirley MacLaine). (Courtesy of PBS)

“Abbey” enthusiasts see potential for conflict between the sharp-tongued Dowager Countess (Maggie Smith, right) and her nouveau-riche American in-law, Martha Levinson (Shirley MacLaine). (Courtesy of PBS)

“I thought she was clearly meant to be Jewish,” he said, “but it’s never stated that she is.”

Regardless of how MacLaine played the part, is it realistic that a member of the British aristocracy would marry a wealthy Jew?

Yes, according to Stansky, who cited several examples of British aristocrats and their rich Jewish wives during an interview in his Stanford office.

“Sybil Sassoon was Jewish and British, although her mother was a French Rothschild,” he said. “She married the Marquess of Cholmondeley.  And Lord Rosebery married an English Rothschild.”

In fact, the show’s very premise — a financially strapped British aristocrat weds a prosperous outsider for her money — was quite common, Stansky notes.

The show’s first episode throws in some authentic historical detail by describing Cora Levinson as a “Buccaneer,” an American heiress of the period who shored up her husband’s floundering finances in return for a title and higher social standing.

“The wonderful thing about the British aristocracy was that they were both incredible snobs and very realistic,” Stansky said. “A Jew was no more vulgar to them than an American.”

(Even so, when pressed to give an example of an aristocrat who married a Jewish American, Stansky could not think of one. )

Jonathan Sarna, a professor of American Jewish history at Brandeis University, was also at a loss when asked to name a Jewish Buccaneer. Julian Fellowes’ decision to make the Levinsons Episocoplian rather than Jewish, he explained by phone, rings true from a historical perspective.

When it comes to the series’ Jewish elements, Fellowes is on the mark

“The Chronicles of Downton Abbey” quotes Fellowes explaining how Isidore Levinson could have been Jewish, while his wife and daughter were not: “He didn’t convert, but allowed his children to be brought up as non-Jewish for ease of life. This was quite usual then.”

Indeed, Sarna confirms, the rate of intermarriage among American Jews during the “Downton Abbey” era was very low, as shown by records from Cincinnati and other Jewish communities. When Jews did marry gentiles, they were usually the sons and grandsons of immigrants who had achieved great wealth, not the daughters and granddaughters.

“It was common for these men to allow their children to be raised as Christians,” Sarna said. “At that time, it was widely accepted in American society that the children would be raised in the mother’s faith.”

And what about the seeming discrepancy between Lady Cora’s online bio, which states that her family is from Cincinnati, and on-air dialogue about her mother’s homes in New York City and upscale Newport, RI? This, too, fits historically, Sarna says.

“Cincinnati was built on the river trade, and the city began to decline with the rise of the railroads,” he explains. “It would have been very plausible for Martha to have left Cincinnati for either the East Coast or Chicago, as did [Reform leader] Rabbi Isaac Mayer Wise’s daughter.”

(Representatives of Julian Fellowes declined to comment on his research and decision to make the Levinsons non-Jews; in an email, his niece told The Times of Israel she didn’t “want to talk on Julian’s behalf in terms of his choices for his characters.”)

Those who’ve followed “Downton Abbey “ since its debut know the series has been both praised and criticized for its depiction of history; overall, the jury is still out. But with regard to the show’s Jewish elements, Fellowes is on the mark.

And in a way, avoiding a Jewish angle may be a good thing, since the absence of Yiddishkeit frees viewers from the strain of trying to catch references within the show’s famously quick, witty dialogue.

That may be disappointing for those hoping to use their Jewdar, but at least we now have a definitive answer to the all-important question plaguing us this past year.

How Jewish is Lady Grantham? Not at all.