She is played by Melissa Joan Hart. Katrina first appeared in the Season Three finale, "The Good, the Bad, and the Luau," after Sabrina figured out the family secret: that every Spellman has a twin. At first, Sabrina enjoyed having a twin and loved spending time with Katrina, but later on, her aunts informed her that Katrina could be her evil twin, revealing that in every set of Spellman twins, there is always a good one and an evil one. A tribunal is held between Sabrina and Katrina to find out which twin is the evil one, and it ends with Sabrina failing the test and being labeled as the evil twin.