The original pilot for "The Big Bang Theory" most notably is missing Penny (Kaley Cuoco), and instead, there's a character named Katie, played by Amanda Walsh.

Audiences didn't take fondly to Katie, who they thought was too abrasive, so the creators, Bill Prady and Chuck Lorre, scrapped, retooled, and recast the character.

For Walsh, the fact that the character was totally rehauled made the process much easier than had she just been subbed out with a different actress.

"I think it was a huge help that the show wasn't exactly the same as that first pilot," Walsh recalled in "The Big Bang Theory: The Definitive, Inside Story of the Epic Series."

She continued, "The fact that it wasn't immediately picked up and there was such retooling made it an easier pill to swallow."

Some unaired pilot actors are swept into the ash heap of TV history, but the "Big Bang Theory" team was kind enough to hold onto Walsh's number.

A year after, Prady called Walsh for his next project — a pilot

for "The Mastersons

of Manhattan" starring Molly Shannon and Natasha Richardson.

Walsh went on to say, "For me, that really validated the notion of 'It's not you,' [...] So, to get rehired by the same people for another big project was very, very validating."