Audiences turned out in big numbers Friday night for ABC’s much-anticipated two-hour Bruce Jenner interview on “20/20,” which drew the newsmagazine’s highest ratings in key demos on the night in more than 15 years.

Nielsen estimates that Diane Sawyer’s sitdown with the former Olympic decathlete-turned-reality star averaged a 5.2 rating/17 share in adults 18-49 and 16.9 million viewers overall. That will make it the week’s top-rated program in all categories as well as the top non-sports program in the young-adults demo since the season finale of Fox’s “Empire” in mid-March.

This is the best 18-49 result on a Friday for “20/20” since March 2000, when Barbara Walters interviewed the parents of JonBenet Ramsey. And it’s the highest for any Friday non-sports broadcast on any network since 2003.

“20/20” opened at 9 p.m. with a 4.9 rating/17 share in 18-49 and 16.4 million viewers overall and then grew both at 9:30 (5.1/17 in 18-49, 17.0 million) and 10 (5.4/18, 17.2 million) before dipping in the final 30 minutes (5.2/18, 16.8 million). Roughly 68% of the 18-49 audience for the special was female, according to Nielsen.

“20/20” had been averaging about a 1.3 demo rating and nearly 6 million total viewers year-to-date. And prior to last night, the highest demo rating for the newsmag over the past 12 months had come last May when V. Stiviano, the female friend of disgraced Los Angeles Clippers owner Donald Sterling, sat down for an interview with Barbara Walters (a 1.7 rating/6 share). Its largest overall audience during the past 12 months also came last May, for the two-hour “20/20” special “Barbara Walters: Her Story,” which drew 9.6 million.

The largest audience for any Friday non-sports program during this television season was the 12.86 million who watched CBS drama “Blue Bloods” on Jan. 9.

“Bruce Jenner: The Interview” would have drawn even more viewers on a night other than lightly watched Friday, and as a result this might be the first example of a highly promoted primetime interview — generally seen as must-watch that night — that will fare reasonably well in DVR playback in the days ahead.

Last night’s interview, of course, was also a very big topic of conversation on social media. According to Nielsen Social, “Bruce Jenner: The Interview” drew 972,000 tweets from 403,000 unique authors, ranking as the most social Friday telecast of all time, excluding sports. Sawyer’s interview with Jenner outperformed the prior record-holder, ABC’s “Megastunts: Highwire Over Niagara Falls — Live!” in June 2012, by 155% in unique authors and by 237% in total tweets.

Following general program descriptors including #brucejennerabc, #brucejenner and #brucejennerinterview, the top hashtags used on Twitter for the interview were phrases of support: #brave and #bebraveenoughtobekind.

Relative to the competition on Friday night, ABC with “Bruce Jenner: The Interview” and “Shark Tank” in its new 8 p.m. timeslot (1.7/7 in 18-49, 7.8 million viewers overall) outdrew the combined demo totals of rivals CBS, NBC and Fox (2.9) and drew nearly as many total viewers as them combined (13.8 million vs. 14.4 million). For the night, ABC’s 4.0 rating is the highest for any network on a Friday (excluding sports) since NBC in April 2003.

“Shark Tank” was up 13% from its most recent original of last week at 9 p.m. (1.5) — and the show is certain to adjust up to a 1.8 in the nationals, which would mean a 20% surge.

NBC’s “Dateline” impressively matched its week-ago rating (0.9/3 in 18-49, 4.3 million viewers overall) despite airing the same time as the “20/20” special. CBS’ “Blue Bloods” was the show most affected (1.0/3 in 18-49, 9.8 million viewers overall), hitting season lows.