In one of the closely watched and highest-profile series renewals in years, CBS will have to make a new deal with Warner Bros TV for the biggest comedy on television, The Big Bang Theory, whose current three-year renewal by the network is up at the end of this season, Big Bang‘s tenth.

“We are in negotiations,” CBS Entertainment president Glenn Geller told Deadline during the TCA press tour in Pasadena. Like the last time around, the studio and network likely will hammer out a new license deal before negotiating new contracts with the cast. (Talks with the actors have not started yet I hear.)

“It is business as usual,” Geller said. “These are going to be, I think, the normal tough negotiations when you in a situation like this but we are guardedly optimistic.”

Three years ago, the network had signed a new three-season renewal for Big Bang by March 2014, a couple of months before the end of Season 7. The new deals with the actors did not close until late summer that year, briefly delaying start of production on Season 8.

There is a new wrinkle this time as CBS also has The Big Bang Theory prequel project Sheldon in the works, which should help the Big Bang renewal.

In Season 10, The Big Bang Theory is still the most-watched scripted series on television and is challenging NBC’s Sunday Night Football for the top spot in total viewers among all programs. It finished the 2015-16 season with more than 20 million viewers per episode (Live+7).