Betty is the "joy and the laughter" of the Powerpuff Girls of the future, Powerpuffs 2099. She is a genetically and cybernetically-modifed clone of Bubbles Utonium of the original Powerpuff Girls. Her sisters are Blitz and Beatrice.
Betty is very similar to Bubbles as far as her physical appearance goes. Her hair is similar to original Powerpuff Girl Buttercup. She is often seen wearing the typical uniform Powerpuffs 2099 clothing, which consists of a light blue and golden chestplate with a pink, blue, and green heart-shape inside it, two shoulder-blades coming from off the sides of the shirt, navy blue pants, and her grey booster-boots.