Kaley Cuoco as Penny
Kaley Cuoco as Penny in The Big Bang Theory CBS

CBS's series The Big Bang Theory rose to success since its premiere in 2006 to become the highest- rated comedy on the network. Kaley Cuoco, who plays Penny on the show, spoke to Variety about the show's success.

In a conversation with Anthony Anderson (lead actor of ABC show Black-ish) as part of Variety's "Actors on Actors" series, she said, "We know better than anyone. It's hard to do a pilot, let alone get picked up for a season, let alone keep going. Our characters have always been lovable, they were the underdogs from day one, and people fell quickly in love with them and wanted them to win, wanted them to do well."

She gave a nod to the consistently funny writing by show creator Chuck Lorre. "Mixed with unbelievable writing and Chuck Lorre, I mean we have this golden God writing behind the scene and keeping things funny."

Cuoco has expressed her shock at the show's prolonged rating and spoke about that eventual end. "Every single day, we're shocked when we look at ratings. We're shocked that the people still want to see us. We love being there and you know, I don't ever want it to end, but you know how it is." The show has already been renewed for two more seasons, Season 11 and 12 by CBS recently.

The show also stars Jim Parsons as Sheldon Cooper, Johnny Galecki as Leonard Hofstadter, Simon Helberg as Howard Wolowitz and Kunal Nayyar as astrophysicist Raj Koothrappali. According to 31-year-old actress, the friendly chemistry between the cast is real as Cuoco added, "We really like each other."

The dynamic between socially awkward geniuses leaves the fans rooting for the characters, said the actress. "They fell in love early on with these four guys and wanted them to get the girl, wanted them to get the job, and it made science kind of sexy."

The full interview between the two actors will air in Variety's "Actors on Actors" Season 6, presented by Shutterstock, which premieres Tuesday on PBS SoCal.

Big Bang Theory
Actor Kunal Nayyar, actress Kaley Cuoco, actress Melissa Rauch, actress Simon Helberg, actress Mayim Bialik, and actor Johnny Galecki attend the People's Choice Awards 2017. Christopher Polk/Getty Images for People's Choice Awards