  We determine the fusion rules of the equivariantization of a fusion category
$\mathcal{C}$ under the action of a finite group $G$ in terms of the fusion
rules of $\mathcal{C}$ and group-theoretical data associated to the group
action. As an application we obtain a formula for the fusion rules in an
equivariantization of a pointed fusion category in terms of group-theoretical
data. This entails a description of the fusion rules in any braided
group-theoretical fusion category.
