In just a few hours, the world will know how to talk about Bruce Jenner again.

Diane Sawyer’s much ballyhooed sit-down with the 1976 Olympic decathlon gold medal winner-turned-Kardashian patriarch is scheduled to air tonight at 9 PM ET, ending weeks of speculation, not as to what he will say, but how he will say it, at what point in the two-hour interview he will say it, what he’ll be wearing when he says it and myriad other questions too embarrassing and/or idiotic to mention.

So secretive has ABC News been about the interview that lisademoraescolumn__140603223319the first on-air promo it released this week did not even show Jenner’s face. That 15 seconds of the back of Jenner’s head and shadows featured only Sawyer’s well-lit face, and the voice-over promised only to reveal “the journey, the decisions, the future.”

News reports have speculated gingerly that the interview is “expected to touch on transgenderism,” with some twisting themselves into knots trying to avoid using pronouns. Others are going the less sensitive/more skin-crawling route, writing about Jenner-interview-watching drinking games, etc.

Meanwhile, Sawyer’s interview walk-up march this morning, through Good Morning America, Live With Kelly And Michael and The View, was maybe the most coy in TV history:

“Tabloid headlines, so much speculation. … Everyone wants to know what’s going on!” ABC News’ Chief Anchor George Stephanopoulos wondered at Sawyer this morning.

“Ah, George, I think we can all agree some things, some stories, should only be told by the person who lives them,” Sawyer tap-danced. “I’m going to let him say first what he wants to say.”

ABC News made it official two weeks ago, announcing Sawyer would interview Jenner tonight on a special edition of 20/20 called, uninformatively, Bruce Jenner – The Interview. Not coincidentally, this year’s May sweep ratings derby began last night. The interview with Sawyer is expected to be the first discussion of Jenner’s transition by a major news outlet.

Sawyer this morning showed Kelly Ripa and Michael Strahan a teensy clip, in which Jenner is heard saying he’s excited about the future” and was looking to see “what I could do, to do some real good in the world.”

According to an informed source, among the reasons Jenner decided to do this sit-down was his surprise at learning the very high rate of attempted suicides by transgender individuals, which Sawyer will discuss in the interview. He is hoping to save lives, the insider said.

This afternoon the jury was split as to whether the interview will score a gigantic audience or only a much better number than a newsmagazine broadcast on a Friday night typically can expect — but with a wildly younger demo skew, what with Jenner being patriarch of the Kardashian clan. Some forecast that a good-ish chunk of 20/20′s older viewers might opt out.

Either outcome would be great for ABC News, because when was the last time millennials made 20/20 appointment viewing? The newsmagazine’s Friday edition this season is averaging about 6.2 million viewers, only 585,000 of them are ages 18-34. Meanwhile, 4.1 million of them are ages 50+, aka people who saw Jenner win the decathlon in 1976. (For comparison sake, ABC’s Shonda Rhimes-created Washington romp Scandal averages 2.5 million millennials this season).

The interview is critically important as well for Sawyer, who stepped down as anchor of ABC World News Tonight in August, saying she would concentrate on big specials and big interviews. Jenner’s first sit-down certainly checks all those boxes, and then some. Sawyer’s in line to take over the crown as Reigning Queen of The Big Get, what with Oprah now busy running, and starring on, OWN and Barbara Walters semi-retired. Back in February, when word got out Sawyer had landed this interview, it was a bit of an embarrassment for NBC News, given that Jenner’s a home-grown star — NBCU being the parent of E! Entertainment, where the various Kardashian reality series reside, and doubly embarrassing what with Jenner being an Olympic icon and NBC being the broadcast network of the Olympics.

“When you’re choosing someone to interview you about a topic this important, [Jenner] was so smart, because you are the only person that could give this interview what it deserved, quite frankly,” Ripa noted, accurately, this morning on her show, when Di came to call.

To break a ratings record, Sawyer’s sit-down with Jenner would have to outstrip the 49 million who watched in March 1999 when Monica Lewinsky detailed Walters her love of President Clinton. Even more daunting is the crowd of 62.3 million who watched Oprah’s interview with Michael Jackson in February 1993.

But Sawyer’s no slouch in the ratings department; her 1995 interview with Jackson and then-wife Lisa Marie Presley averaged 37.5 million viewers. More recently, however, Sawyer’s 2013 exclusive interview with Amanda Knox logged an average of 8.5 million viewers, which was only about 800,000 viewers ahead of CBS’ original episode of  Golden Boy in the same hour. Sawyer’s sit-down with Knox had been the first TV interview for the Seattle college student convicted of murdering her roommate in Italy in 2009. The Italian Supreme Court overturned her conviction last month.

In November 2011, 12.4 million tuned in when Sawyer interviewed Rep. Gabrielle Giffords, 11 months after the lawmaker was shot in the head in an assassination attempt. And in March 2012, more than 15 million viewers watched Sawyer interview Jaycee Dugard about her kidnap from a South Lake Tahoe bus stop and 18-year captivity, during which she gave birth to two children conceived by rape.

Anticipating a press feeding frenzy, if not a bona fide ratings tsunami, ABC News this morning had sent the media a set of No Rannygazoo Guidelines. Among the highlights, the news divison warned:

Excerpts of no more than ONE MINUTE (1:00) of actualities from “20/20” may be incorporated in your regularly scheduled news programs broadcast within the seven (7) day period commencing at 3:35 a.m. ET Saturday, April 25 following the West Coast airing of Nightline

And…

A mandatory on-screen credit reading “ABC News Exclusive” must be aired during the entire excerpt you broadcast. The excerpt must be introduced with an audio credit “In an interview with ABC News’ Diane Sawyer…”

And…

With regard to any possible excerpting by your network of the interview, please note that we expressly forbid the use of logos over any of the above footage. If it is not possible for you to excerpt the program without showing a logo, then there may be no excerpting.

Meanwhile, David Brock’s politically progressive watchdogging and lobbying group Media Matters for America sent the press, “The Dos and Don’ts Of Talking About Bruce Jenner’s ABC Interview.” It included:

DO Highlight The Realities Of Being Transgender

DON’T Fixate On Jenner’s Appearance

DO Use Proper Terminology

DON’T Focus On Surgery

Meanwhile, what about the Kardashians? TMZ, the in-house newsletter for their various E! TV series, reports that Jenner will watch the interview twice at his home, with different members of his extended family, for separate East and West Coast feeds.

Sawyer referenced Jenner’s family when she spoke to Stephanopoulos this morning, saying: “I think you’re going to learn about family love. This is a family love story.”

“It’s a journey a lot of the country is looking at as well,” Stephanopoulos said course-correctingly, to bring Sawyer back to the actual, you now, news here.

“Understanding. Understanding. Learning tonight,” Sawyer emoted.