The ubiquitous Charlie Sheen is a ratings tonic for the networks.

Monday saw a Sheen showdown in primetime, where a 9 p.m. repeat of “Two and a Half Men” on CBS stood as television’s most-watched program (11.6 million), up a bit week to week. At the same time, Sheen helped spike viewership on CNN’s lightly watched interview show “Piers Morgan Tonight.”

Meanwhile, CBS boss Leslie Moonves couldn’t avoid a “Men” question during his Tuesday appearance at the Morgan Stanley media and technology investor confab in Gotham.

Moonves noted that in the short term, CBS will save some money in not having to shell out the license fee (an estimated $4 million per episode) for the eight remaining segs of this season, particularly because “Men” repeats perform so well.

“Short term financially, it’s actually a gainer for us. Repeats obviously get somewhat less revenue than the originals (but) this is a show that repeats very well,” he said. “Doing eight less originals saves us quite a bit of money. I am not saying long term I want this to go on.”

Moonves allowed, “I hope it’s back” at some point — indicating that CBS and Warner Bros. have not written “Men” off entirely for next season — but in regards to Sheen’s 24/7 media blitz of the past few days, he couldn’t help but say, “I wish he would have worked this hard to promote himself for an Emmy.”

Morgan’s hourlong chat with Sheen averaged 1.35 million viewers — the host’s largest aud since his premiere-night talk with Oprah Winfrey — while drawing the show’s biggest audience to date among adults 25-54 (561,000). It still lagged its news competition on Fox News, “Hannity” (2.62 million, 751,000 adults 25-54).

The repeat airing at midnight ET (9 p.m. PT) scored a strong 719,000 viewers and 354,000 in 25-54, making CNN the cable news leader in the demo opposite FNC’s “Hannity” encore (267,000 in 25-54, 764,000 overall) and MSNBC’s “Maddow” repeat (185,000 in 25-54, 511,000 overall).

Earlier in the day, ayem news shows “Today” on NBC and “Good Morning America” on ABC saw ratings bumps thanks in part to Sheen.

Even though the Alphabet show was well above average with 5.94 million viewers (thanks to both post-Oscars coverage and clips of its Tuesday night “20/20” special with Sheen), the Peacock program remained a leader with 5.97 million viewers. “Today,” which had averaged 5.45 million viewers a week earlier, featured its own Sheen interview. ABC, meanwhile, was expecting good numbers for its hourlong “20/20” spec Tuesday night devoted to Sheen and his “goddesses” — although maybe not as big as it had once anticipated. The net believed it had an exclusive interview with the actor before his Monday speaking spree, which also included several radio programs.

Also Tuesday, Sheen apparently discovered Twitter. An account with a verified tie to the actor surged to 200,000 followers after just a few hours, with only one tweet — a photo of Sheen and a gal pal posing with chocolate milk and Naked Juice, respectively.