"The Big Bang Theory" is an American television sitcom. The CBS series follows the life of Leonard Hofstadter and Sheldon Cooper, two physicists from the California Institute of Technology. These two men are rather clueless when it comes to anything other than science. And so, the comedic series follows their interactions with fellow science boffins and also with the ladies in their lives. The main ladies in the show are played by Kaley Cuoco, Mayim Bialik and Melissa Rauch.

Don’t miss on the latest updates Follow the TV Shows Channel

All three of these ladies have pretty amazing back stories that you may never have guessed just by watching the show!

Kaley Cuoco

Cuoco plays Penny, Leonard's love-interest in the series.

In the series, she is known as a bit of a ditz - your typical dumb blonde. She is well-loved nonetheless and no one can imagine a show without her in it. However, Cuoco wasn't actually the first choice for Penny's role. The role was initially played by Amanda Walsh. However, CBS turned down the first pilot of the show featuring Walsh. According to Fox News, CBS decided to air the show at a later stage when they saw a new pilot featuring Kaley Cuoco. The rest is history.

Another amazing fact about the blonde beauty is that she is actually quite the tennis fanatic. According to CBS, the star started playing tennis at age 3. She was a nationally-ranked amateur tennis player before she made it big as an actress.

Mayim Bialik

Turns out, Sheldon Cooper's genius girlfriend is quite the genius in real life too.

Top Videos of the Day

Bialik plays Amy, a neurobiologist. In real life? Bialik is a neuroscientist. She turned down both Harvard and Yale to study at the University of California. So, as it turns out, she's not just saying words on set, the star really knows her stuff!

Another interesting fact about Bialik, according to CNN, is that Bialik has written her own book on parenting. She also makes her own shampoo and refuses to use commercial hair products. Bialik has two sons of her own as well. Talk about a busy lady!

Melissa Rauch

Rauch plays the role of Bernadette. According to Fox News, the star has always been a fan of NPR and "The Big Bang Theory". She told the press that she feels a lot more comfortable around nerds than around anyone else. One of the most astounding things about Rauch is that she was actually one of the show's biggest fans before she was cast. So, when the star was welcomed on set, she had to work really hard to show her absolute awe.

Well, there you have it. "The Big Bang Theory" just gets better and better. The men may be the stars of the show but the women certainly hold their own in real life!