London - The Big Bang Theory stars Kaley Cuoco, Jim Parsons and Johnny Galecki want $500 000 per episode.
The three leads in the sitcom - who play Penny, Sheldon and Leonard respectively - are reportedly seeking a big pay rise as the show continues to be a huge success.
According to reports on Deadline.com, the trio are negotiating their deals collectively - as they have done since 2010 - and all want a considerable raise on their current salary of $325 000 per episode.
It has also been claimed two of the cast's newest members - Mayim Bialik and Melissa Rauch - are set to renegotiate their own contracts.
The duo - who became show regulars in 2010 after starting off as guest stars - currently earn between $20 000 and $30 000 for each episode, but this could double.
Their pay is then expected to increase every year and could peak at $100 000 an episode by the end of their contracts.
It is claimed Kaley - who previously dated 'Man of Steel' star Henry Cavill - was "overwhelmed" by her love life being so public, despite her success in the sitcom.
A source previously said: "She just got overwhelmed with the very public Superman relationship. She's not used to that much attention and chaos in her life." - Bang Showbiz