The Big Bang Theory might be one of CBS's most popular shows, but it's also its most expensive. Now starting its 11th season, with a 12th already confirmed, The Big Bang Theory has a strong and dedicated fanbase, which one could argue makes its stars' salaries worth it. Much has been made of just how much the show hands over to keep Jim Parsons, Kaley Cuoco, and Johnny Galecki in their roles, and last year all three re-negotiated their contracts with the channel. Their co-stars have also spoken up, though, negotiating deals that saw huge pay raises that brings them much closer to Parsons, Cuoco, and Galecki's pay checks. So just how much do they earn? The answers might surprise you.

Kaley Cuoco, Jim Parsons, and Johnny Galecki

Let's be clear; The Big Bang Theory wouldn't be the same show if  any one of this trio were to quit. While we still don't know exactly how long the show will run for, it's a safe bet (with 12 seasons confirmed) that the end will come sooner rather than later. So it makes sense that CBS will do all it can to keep its main stars on the show.

Back in 2014, all three re-negotiated their contracts to raise their salary to a massive $1 million per episode. That figure was also the amount each of the cast of Friends pulled in for their final season, but bear in mind that The Big Bang Theory stars negotiated this salary in 2014 - with at least five more seasons ahead of them.

However, Cuoco, Parsons and Galecki have now agreed to take a cut in their salary, in order that the pay of their co-stars, namely Melissa Rauch and Mayim Bialik, can be increased. So from season 11 onwards, the trio will be down to $900,000 each per episode. That said, with 22 episodes a season, this will still net them each nearly $20 million a season.

It's also worth pointing out that all three have negotiated a deal with Warner Bros. to make an undisclosed sum off the backend of the show, while Parsons and Galecki have also extended their overall deal with Warner Bros..

Kunal Nayyar and Simon Helberg

The cast of The Big Bang Theory falls neatly into three categories, and Nayyar and Helberg sit right in the middle. They were never paid on par with Cuoco, Parsons and Galecki, but neither were they bottom of the heap. For seasons 8 and 9, it was rumored that they took home $750,000 per episode, but contract re-negotiations saw a specific clause put in for both that brought them in line with the three main stars.

For season 10, they enjoyed a cool $1 million per episode, but they too have agreed to a pay cut going forward, and are now on $900,000 per episode. Like Cuoco et al, their deals also include a profit deal from the backend of the show.

Melissa Rauch and Mayim Bialik

Granted, Rauch and Bialik didn't become series regulars on The Big Bang Theory until season 4, so prior to that it'd be expected that they didn't earn a pay check on a level with the main cast. Even so, when Rauch and Bialik negotiated new contracts in 2013, prior to season 7, it was reported that they were still only taking home $60,000 per episode. That gradually increased to $100,000 per episode but that's a massive difference, especially considering how integral their characters have become to the show.

With their contracts now up, the pair are rumored to be seeking parity with their co-stars, but it's highly unlikely they'll achieve it. However, they are said to be in line for a massive pay rise, mainly thanks to the cuts taken by the other five main cast members, which will see their wages increase to $450-500,000 per episode. Even at the top end, that's still $400,000 short of the other five; pretty galling when you all do the same job with pretty much the same amount of work.

So, CBS are now set to be shelling out $7 million per episode for The Big Bang Theory, and that's just on the main cast's pay. Add in production costs, wages for the writers, producers, directors, and so on, and it's easy to see why it's CBS most expensive show. The question is, is it worth it?

Next: The Big Bang Theory: 20 Pictures The Cast Doesn’t Want You To See

The Big Bang Theory season 11 starts Monday, September 25th, on CBS