Kathy (Paget Brewster) — Joey's girlfriend, introduced in "The One with Joey's New Girlfriend" (Season 4, 1997), with whom he has nothing in common apart from both being actors. A mutual attraction develops between Kathy and Chandler in "The One with the Dirty Girl" (Season 4, 1997), which manifests as a kiss in "The One Where Chandler Crosses the Line" (Season 4, 1997). After Joey finds out, Kathy decides to leave New York for Chicago, and declares her love to Chandler in "The One with Chandler in a Box" (Season 4, 1997). Initially outraged at Chandler's betrayal, Joey has a change of heart after Kathy's speech, and she and Chandler get together. She sleeps with a co-star in "The One with Rachel's Crush" (Season 4, 1998) and Chandler dumps her.
When Paget Brewster arrived for her audition, she believed she was the "runty alternate" and did not have a chance of getting the part. Matthew Perry later told her that the producers knew she was right for the role when she called herself a "runt". She spent her first two weeks working on the show believing that she would be fired and the part recast with a better looking actress. Brewster did not want Kathy to be written out by cheating on Chandler. The female stars agreed with her and tried to persuade the producers to have Kathy tour in a play instead.