Aida-Effect
The Aida-Effect describes a pretty person, who dresses in a "gammellook" in everyday life, but when the occasion arises e.g. in the Opera she really shines and the Aida effect kicks in. There is hardly any boys who can't resist to look at her and turn around when she passes to check her.
A Boy: I can't believe she looks that good when the Aida-Effect Kicks in.