Filming for Season 8 of "The Big Bang Theory" is supposed to start on July 30, but production is currently at a stand-still because the show's lead stars don't have new contracts yet. According to The Hollywood Reporter, Johnny Galecki (Leonard), Jim Parsons (Sheldon) and Kaley Cuoco (Penny) are all still trying to negotiate deals with Warner Bros. Television.

Because "The Big Bang Theory" was renewed, the trio is seeking significant raises for Season 8. Back in September the trio asked for raises but a source told THR that there has been no movements in the negotiations since then.

However, Warner Bros. Television is confident that something will be worked out before the new season begins. According to THR, Galecki, Cuoco and Parsons are expected to return to work at the end of the month, whether a deal has been worked out or not.  

It was previously revealed that the trio wanted to raise their salaries to $1 million per episode; they currently earn $325,000 an episode. Parsons, Galcki and Cuoco have decided to negotiate the deals together.

"They know the critical position 'Big Bang' holds on CBS's prime-time schedule and the only thing preventing them [from] getting what they want would be a spectacular demise this season," a source previously told Radar Online about the salary negotiations. "That isn't about to happen anytime soon. They'll put on a united front during negotiations."

Their co-stars Mayim Bialik and Melissa Rauch have already worked out new deals and received raises. Reportedly they went from making $20,000 an episode to almost $60,000 per episode. By the end of their contracts, Bialik and Rauch could earn up to $100,000 for one episode.

"The Big Bang Theory" ended Season 7 in May with Sheldon possibly leaving town on a train because he was overwhelmed at all the changes happening in his life. Season 8 will return Monday, Sept. 22 and then move back to Thursdays starting Oct. 30.