CBS and Warner Bros. TV are close to sealing a $260 million-plus three-season renewal pact for “The Big Bang Theory.”

The Eye and Warner Bros. have been quietly negotiating the renewal for some time and are said to have settled on the major points shortly before the holidays. Reps for CBS and Warner Bros. TV declined to comment, but the deal is said to cover 66 episodes — 22 segs per season — at a license fee of about $4 million to $4.5 million. That’s a big bump from the Eye’s current license fee of a little more than $1 million per seg. The deal takes the show, co-created by Chuck Lorre and Bill Prady, through its seventh season.

“Big Bang” is a rare example of a primetime skein that would have been a free agent after its license term with CBS expired at the end of this season.

In most instances, networks insist on perpetual license fee agreements at the pilot stage to guard against the threat of a studio leveraging a show’s success down the road to an “ER”-level license fee — as Warner Bros. was able to do in 1998 when “ER”was at its peak and up for renewal. (“ER’s” $13 million license fee from NBC is a biz record that is unlikely to be broken anytime soon.)

But “Big Bang” hails from the Chuck Lorre Prods. hit factory, which meant that Warner Bros. had clout from the start to secure optimal contract terms for the show and nix a perpetual license fee provision.

“Friends” in its heyday commanded a $10 million license fee, primarily because the six stars were pulling down $1 million a seg apiece. By contrast, “Bang’s” three primary stars, Johnny Galecki, Jim Parsons and Kaley Cuoco, are making six-figure salaries after recent salary renegotiations.

Moreover, the economics of primetime TV are much changed since the “Friends” era. The renewal deal was reached between top brass at WBTV and CBS without any fireworks and without threats of WBTV taking “Bang” to the highest bidder among the Big Four nets. It’s understood that both camps recognized early on that there was little to be gained by moving the show from its original network home.

The renewal deal with CBS puts “Bang’s” profitability into the stratosphere. Warner Bros. inked a record-setting off-network syndication sale for the show in May that calls for TBS to pony up $1.5 million a seg for the rerun rights, plus WB will reap even more coin from syndie sales to local stations and from barter advertising sales once the reruns begin airing this fall (Daily Variety, May 17).

In March 2009, when “Bang” was at the tail end of its second season, CBS gave the show a two-season renewal, along with a three-season pickup for “Two and a Half Men,” also from Chuck Lorre Prods./WBTV. Since then, “Big Bang” has blown up into a tentpole hit for the Eye and a force in the pop culture zeitgeist.

This season, the Eye took the risky move of moving the show from its Monday 9:30 p.m. berth behind “Men” to the Thursday 8 p.m. anchor slot. “Bang” has more than met the challenge. For the season to date, “Bang” is running neck-and-neck with ABC’s “Grey’s Anatomy” and “Modern Family” for the mantle of primetime’s top-rated scripted skein in adults 18-49, with “Bang” averaging a 4.8 rating to “Grey’s” 5.0 and “Family’s” 4.9.

In total viewers, “Bang” ranks No. 11 among all primetime skeins with an average of 13.9 million. Among laffers, it’s No. 2 behind “Men” (14.7 million).

On the “Men” front, there was much discussion on Tuesday about the physical health of star Charlie Sheen and whether the network and studio were considering shutting down production in light of Sheen’s personal issues.

As of Tuesday, production on “Men” was proceeding without interruption. Sheen spokesman Stan Rosenfield issued a pointed statement in response to an online report asserting that Sheen had not reported for duty on the Warner Bros. lot.

“Memo to Chicken Little: The sky remains in place,” Rosenfield said.