Lea

Léa, from in Search of Lost Time, by Marcel Proust.
Léa is a character who doesn't appear in the novel-well only, once, seen from a distance, and the narrator doesn't even know it is her, yet-, but is largely spoken of (Like Maris in Frasier, ).
She is an actress, a lesbian or rather bisexual like most women in Proust. If a character admited to knowing her, people would gasp in shock, like this