The top "Big Bang Theory" stars are demanding a huge salary increase for the eighth season. Jim Parsons (Sheldon), Johnny Galecki (Leonard) and Kaley Cuoco (Penny) are banding together and will negotiate for bigger paychecks.

According to The Hollywood Reporter, their co-stars Mayim Bialik (Amy) and Melissa Rauch (Bernadette) have already received raises and also landed new deals with Warner Bros. Television that will guarantee "a long-term presence on the series."

Sources told THR that Parsons, Galecki and Cuoco - who currently make a reported $325,000 an episode - want to earn as much as $1 million an episode. Simon Helberg (Howard) and Kunai Nayyar (Raj) are also said to be looking for significant pay increases and will negotiate together.

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

The trio banned together in 2010 and the cast of "Friends" also famously did something similar in 2002. Jennifer Aniston, Courteney Cox, Lisa Kudrow, David Schwimmer, Matt LeBlanc and Matthew Perry all got together and asked for an increase that would give them a pay raise of $1 million an episode during the last season.

The new deals already in place for Bialik and Rauch will see their salaries go from about $20,000 an episode to almost $60,000. By the end of their new contracts they could make up to $100,000 per episode.

"What they've been able to achieve is a feat unheard of for a show in recent history and they all deserve to get compensated for it," the source continued talking about how successful the series has been.

The "Big Bang Theory" is the highest rated syndicated show and has been nominated for eight Emmy awards. It's sixth season ended with 18.6 million viewers and a 6.2 rating in the key adult 18-to-49 demographic, the Daily Mail reports.

The seventh season of the "Big Bang Theory" kicks off Sept. 26 on CBS.