Broadcast TV's No. 1 comedy isn't going anywhere.

CBS and producers Warner Bros. Television have officially closed a two-season renewal for The Big Bang Theory, The Hollywood Reporter has learned. Sources tell THR that co-stars Mayim Bialik and Melissa Rauch are still without contracts, though both are expected to return once a new deal can be worked out.

The new pact will take the multicamera comedy from Chuck Lorre, Bill Prady and showrunner Steve Molaro through its 12th season. It's unclear if season 12 will be the show's swan song.

Sources say new deals for stars Jim Parsons (Sheldon), Johnny Galecki (Leonard) and Kaley Cuoco (Penny) will see the trio take a pay cut to $900,000 per episode — down from the $1 million per episode and points (1.25 percent) of the show's lucrative backend that they scored three years ago. Original stars Simon Helberg (Howard) and Kunal Nayyar (Raj) were upped to the show's top tier as part of their last round of contract renegotiations. (Parsons, Galecki and Helberg all received overall deals with WBTV as well.) All five original stars are said to be earning $900,000 per episode as they took pay cuts to help boost the contracts for co-stars Bialik and Rauch.

Rauch (Bernadette) and Bialik (Amy) are holding out for salary parity with their co-stars after signing on to the series in season three. (Both are integral to the show, with Bernadette now married to Howard and Amy living with Sheldon.) Rauch and Bialik are seeking significant raises from the $175,000 per-episode fee they negotiated three years ago. The duo, who are negotiating together, are not expected to get parity, though they are considered very likely to score more than $400,000 per episode.

Big Bang Theory comes with a hefty production cost of $10 million per episode. Sources note that CBS and WBTV are expected to jointly cover those costs. In its 10th season, Big Bang Theory remains a key property for CBS and WBTV, ranking as broadcast's No. 1 scripted series in total viewers, adults 18-49 and adults 25-54. The network uses the comedy as a launchpad for new half-hours. CBS Corp. CEO Leslie Moonves recently said that the newly ordered Big Bang Theory spinoff Young Sheldon — which is narrated and executive produced by Parsons — would likely secure that primetime slot next season.

The renewal sets Lorre up to have three series on CBS next season, with Young Sheldon and Big Bang Theory likely joined by critical darling Mom, though a renewal has yet to be announced for that comedy. Meanwhile, Galecki also scored a pilot pickup this season at CBS for the comedy Living Biblically.

For CBS, Big Bang Theory joins the previously announced NCIS (and Young Sheldon) on the network's 2017-18 schedule as it handed out early pickups to its most valued drama and comedy.