Katie

File:Vlcsnap-2011-11-20-00h04m53s220.png|thumb|Crying Katie]]Kate was the pre-Penny female lead from the Unaired Pilot produced for the 2006-2007 television season. Katie was played by actress Amanda Walsh, "a street-hardened, tough-as-nails woman with a vulnerable interior". Kate who works at a beauty salon was found by Sheldon and Leonard on the curb crying and left homeless by her former boyfriend. Leonard, despite Sheldon's objections, invites her to dinner and then to stay a few days at their apartment. She is abrasive,, hard, and , but she softens a little when she discovers that the guys aren't trying to get something from her. In the end, she decides she'll crash at their place for awhile. Katie meets their geeky firend Gilda, an early Leslie Winkle prototype, who likes Leonard and is jealous of her until Katie says that she had no romantic interest in the two nerds. Katie goes out drinking and arrives back at the apartment late at night, waking Leonard by smashing a. Katie starts ranting to Leonard about her life and why it sucks, using the, drawing colorful explain her point. Leonard upsets her by suggesting her problems weren't caused by her mother, boyfriend etc., but by her making stupid. As a result, she moves out. Katie comes back at the end of the episode explaining that staying there is her only rent-free choice. She takes Leonard, Sheldon and Gilda out.

The audience did not like the way Katie was mean and mocking toward Sheldon and Leonard, so she was dropped for the second pilot and replaced with Penny who is sweet and caring. Penny does exhibit some of these mena nad mocking traits when she gets real mad at people.