Production on Season 8 of "The Big Bang Theory" has been postponed while the show's main stars continue to work out deals. Kaley Cuoco (Penny), Johnny Galecki (Leonard), and Jim Parsons (Sheldon) all remain without contracts for the new season.

According to E! News, Simon Helberg (Howard) and Kunal Nayyar (Raj) also don't have contracts. Warner Bros. Television confirmed to E! that "due to ongoing contract negotiations, production of 'The Big Bang Theory' - which was originally scheduled to begin today - has been postponed."

Earlier in July Nina Tassler, a boss at CBS, told reporters that the network was not concerned about the standoff, E! reports.

"We're feeling very confident that everything will work out," she said. "These deals manage to get done miraculously somehow year after year."

It's been said that Cuoco, Galecki and Parson all want a raise of $1 million per episode; currently they each earn $325,000 an episode. To make sure the deals go through, Cuoco and her two male co-stars have decided to negotiate their new contracts 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 negotiations. "That isn't about to happen anytime soon. They'll put on a united front during negotiations."

Despite the standstill, "The Big Bang Theory" creator Chuck Lorre previously told E! that he was confident everything would work out.

"It will be fine," he said. "Warner Brothers has done this before. Everybody should be very successful and happy and rich. They earned it. It's a great cast. Great cast. It's their time."

Helberg and Nayyar are also asking for significant raises, while Mayim Bialik (Amy) and Melissa Rauch (Bernadette) have already signed new deals which included raises.

Season 8 of "The Big Bang Theory" returns Monday, Sept. 22.