'The Big Bang Theory' Set Secrets: Stars Share Their Audition Stories - Who Nailed It, and Who Messed It Up?

The cast members of "The Big Bang Theory" look back on their audition days with great fondness, each one of them with a hilarious story attached to their beginnings with the show.

For Melissa Rauch, the actress who portrays Bernadette Wolowitz, she somehow found herself with a weird Canadian accent during auditions.

"I had to say the word 'about,' but I kept pronouncing it 'a-boot,'" Rauch told Glamour. "This was actually during my callback, and Chuck Lorre said to me, 'Are you from Canada?' I said 'No, I'm so sorry!' He asked me to do it again. I did, but I pronounced it the same way! I said, 'I'm really sorry! I don't know why I'm playing this Canadian!'"

Despite her funny Canadian accent, Lorre thought she was simply perfect as Bernadette, and Rauch landed the role anyway.

As for Mayim Bialik, who portrays Bernadette's friend Amy Farrah Fowler, she impressed executive producer Bill Prady with her resume since she included that she has a Ph.D. in Neuroscience.

"He said, 'Is this for real?'," Bialik said. "I didn't know where else to put it on my resume, so I put it under miscellaneous, along with (things like) 'Speaks Spanish, Ph.D. Neuroscience...'"

On the other hand, Simon Helberg, who portrays Bernadette's husband Howard Wolowitz still kept his audition pages because he likes to be reminded just how far the show has come from its roots.

During Helberg's audition, he also sported the exact same haircut that Howard has on now.

"I didn't do it as a nerdy choice, (but just) because I thought it was kind of cool. They said, 'That hair is so nerdy, can you do it again?' I was like, 'Yeah, sure, 'cause I did that for the part! I don't do this everyday.' So then I had to change my hair in life, so I didn't look as nerdy as they thought I did!" he said.

Among the group, it was definitely Jim Parsons who nailed his audition for Sheldon Cooper. Show creator Chuck Lorre was so impressed with his performance that he did not look further in getting an actor to play Sheldon.

"Jim was one of the most startling auditions I've ever seen in my life," said Lorre. "He walked in with this fully realized character. His body language, his gestures, his pauses, his hesitations, his inflections. Everything was so beautifully crafted that he killed it. He just killed the audition. He walked out of the room, and I said to the casting director, Nikki Valko, 'Ask him to come back. I want to see if he can do it again!' It was so startling, we were clearly in the presence of brilliance."