Folded/binned HATNet light curve of WASP-33 (dots) vs the best-fitting blend model (continuous line). There are 400 bins throughout the full orbital period. The standard deviations of the bin averages are very similar, they scatter around 0.8–1.2 mmag. The large out of transit variation of the presumed blended eclipsing binary excludes the possibility of a blend scenario by very high significance.