This endearing nickname name is one Katherine pet form that predates all the Kathys and Katies, having been fairly common in the eighteenth century. With the current mini-craze for animal-related names, Kitty is sounding cute and cuddly again—she's already jumped back onto the U.K. list, at number 199.
Kitty was one of the Bennet sisters in Pride and Prejudice and was a character in Dickens's Bleak House; Ginger Rogers won an Oscar for her performance in Kitty Foyle, and vintage TV fans might remember the alluring Miss Kitty in Gunsmoke. Since then there have been pop culture Kittys galore, including Calista Flockhart's character on Brothers and Sisters, a mom on That 70's Show and Kitty Pryde, one of the X-Men.
Singer Kitty Carlisle was born Catherine, country singer Kitty Wells grew up as Muriel, and Presidential candidate's wife Kitty Dukakis was born Katharine.
A historical reference is Kitty Hawk, where the Wright brothers performed their aeronautical experiments.
Short form Kit has been used in recent years for several strong-willed movie heroines and may prove a lively alternative to Kate.