UPDATED: Playboy Club founder Hugh Hefner weighed in on NBC’s decision to scrub “The Playboy Club” from its primetime schedule owing to lousy ratings.

“I’m sorry NBC’s ‘The Playboy Club’ didn’t find it’s audience,” he tweeted, adding, “ It should have been on cable, aimed at a more adult audience.”

ORIGINAL POST: Those of you wondering what NBC was thinking of when it put its new 60’s-set drama, “Playboy Club” into the intense Monday at 10 competition opposite both ABC’s “Castle” and CBS’s “Hawaii Five-O,” we have an answer!

The season’s first cancellation.

NBC is putting Brian Williams new newsmag — the oddly named “Rock Center with Brian Williams” into ther hour starting Oct. 31, according to an industry source.

“Playboy” was DOA when it premiered during the first official week of the TV season. Despite all the hooplah that preceded its unveiling — including much chest thumping by conservatives, and Gloria Steinhem — all mother’s milk for network marketing suits — the first episode it attracted just 5 million viewers, and it finished last among broadcast networks in its timeslot with the younger viewers NBC targets.

In its second week, the 60’s set show, which has been accused of being a “Mad Men” knockoff, clocked an even more disappointing 4 million viewers — laps behind ABC’s “Castle” (11.7 million viewers) and CBS’s “Hawaii Five-O” (11.3 million) in the same hour.

This past Monday was the final nail in the coffin: the bunnies attracted a puny crowd of 3.4 million, according to early stats, while “Castle” clocked 11.6 mil and “H5-0” hung on to 11 mil. And, once again, “Playboy” was an also-ran among the 18-49 year olds who are the bread and butter of broadcast TV ad sales.

Back in May NBC announced it was developing a new Brian Williams primetime newsmagazine; Meredith Vieira, Harry Smith, and Kate Snow, Matt Lauer, and Ann Curry are among those lined up to contribute.