The three lead cast members of “The Big Bang Theory” are in talks to renew their contracts for the show, according CBS entertainment president Glenn Geller.

“We are in negotiations, but it is definitely business as usual,” Geller told Variety Monday at the Television Critics Association winter press tour Monday. “We are guardedly optimistic that we will make a deal.”

Geller said that there is no timetable to complete negotiations with Jim Parsons, Johnny Galecki and Kaley Cuoco to continue on the Warner Bros.-produced comedy. Asked whether the show could continue without any of the three leads, Geller said, “We want to get them all back. That’s the goal.”

When Parsons, Galecki and Cuoco last renewed their contracts in 2014, they each secured a fee of $1 million per episode for three 24-episode seasons. Geller declined to say whether, should negotiations with all three cast members prove fruitful, the network would renew the Chuck Lorre comedy for multiple seasons.

“The Big Bang Theory” remains TV’s most watched comedy, with its season 10 premiere drawing 21.5 million total viewers. The series has generated more than $1 billion since its 2011 debut in off-network syndication, fueling the ability of the lead cast members to command such high salaries. But the 10 seasons in, the show is not poised to generate significant new revenue in syndication for additional new episodes, possibly limiting the ability of the actors to negotiate a sizeable raise.