Kaley Cuoco throws the "best parties" of the 'Big Bang Theory' cast.

Melissa said: "A lot of us hang out. It's just a close knit group.

"Kaley is the best at throwing parties. Mayim's the deep thinker, and Kunal is a big giggler. We all get along, and it's a nice family feel."

Despite the huge success of the show, the cast insist they haven't changed with fame.

Simon told People magazine: "Everybody's got their feet on the ground, so it doesn't feel that much different than day one."

And the group do their best to keep grounded and have learned how not to attract attention to themselves.

Kaley said: "You learn who to talk to, where to go and how to act.

"If you don't want to be photographed, don't go to The Ivy, and wear undergarments when you go out!"

It was recently claimed the cast had demanded a pay rise of more than 100 per cent for the new series of the show.

They previously earned $300,00 per episode but were looking to strike a new deal, with reports suggesting figures up to $1 million per show.