The massively successful CBS sitcom The Big Bang Theory is about to start production on its eighth season, but the show's stars - Jim Parsons, Johnny Galecki, Kaley Cuoco-Sweeting and others - still haven't signed new contracts.

The Big Bang Theory Season 8 Premiere Date Revealed

The Big Bang Theory's stars and their management are still negotiating new contracts for the upcoming season, as their previous contracts concluded with the recently-ended Season 7. Among those who still haven't signed on just yet are Parsons (who plays Sheldon), Galecki (Leonard), Cuoco-Sweeting (Penny), Simon Helberg (Howard) and Kunal Nayyar (Raj). These five have been starring in the show since Season 1 and have received significant pay increases as the sitcom became more and more successful.

Production on Season 8 is slated for July 30 and the cast's respective management still haven't reached deals with the show's producers. Deadline is now reporting that the two sides are barely talking and may not be anywhere close to reaching a deal.

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Meanwhile, the only two cast members who have signed contracts are recent Emmy nominee Mayim Bialik (Amy) and Melissa Rauch (Bernadette). The two actresses joined the cast in the middle of the series' run, and are therefore on a different contract schedule than the "original five." The actresses renegotiated their contracts in the fall of 2013.

Parsons, Galecki and Cuoco-Sweeting may be getting close to $1 million per episode by the end of negotiations, which is what the cast of Friends was receiving in their final years.

The Big Bang Theory Season 8 is set to have its premiere on Monday, Sept. 22 at 8 p.m. on CBS.

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