Callie was a best friend to Katie Brown since they were babies until she dumped her to join the Popular Girl Club. She can sometimes be nice and other times not. She declares a war on Katie in Katie and the Cupcake War and becomes a rival of the Cupcake Club. .Then Olivia comes and takes over the club and renames it the BFC (best friends club) Then Callie and Katie then had peace together after the Cupcake War and becomes nice in the rest of the books. She and Katie were no longer best friends, but are at least friends. Callie is tall with curly blonde hair and blue eyes. She and Mia get glasses in Mia a Matter of Taste.