10 Insane Rules The Big Bang Theory Cast Had To Follow

Because The Big Bang Theory was such a powerhouse sitcom, it's easy to forget it was nearly cancelled from the get-go. As hard as that is to believe, the unaired pilot had very little in common with the finished product.

Although Lenny and Sheldon were still the main characters, their personalities were quite different, and there was no Howard or Raj. Instead of Penny, a streetwise girl called Katie served as the main female character. Sadly, the test audience didn't gravitate to Katie, deeming her as mean and unlikable. As a result, the creator, Chuck Lorre, had the character revised into the more loveable neighbour, Penny.

Even though it all worked out in the end, Lorre was ashamed of the pilot, since it nearly caused the whole show to be canned. Although snippets of the pilot can be found online, Lorre asked the cast never to discuss it since he didn't want the episode associated with the show. The actors stayed so tight-lipped about it for so long, many die-hard fans of The Big Bang Theory had no idea there was an unaired pilot for years.