This is a sheer chiffon black and white polka dot gown by Christian Dior Haute Couture, from 1980. The gown has an open slit up the front and comes as a three piece set, with a matching scarf and black chiffon belt.
Provenance: Betsy Bloomingdale

Measurements:

Bust: 34 in.

Waist: 29 in.

Hip: 32 in.

Length: 60 in.