This is a bias cut silk chiffon evening gown by Christian Dior, circa 1990's.
It has a halter neck, drop waist, gathered draped chiffon at the hip, and functional covered "bridal buttons" down the side seam.
The body of the dress is nude to hot pink to dark raspberry-purple ombre at the hem.
Left side has a side slit for ease of movement.
The gown is bias cut so there is some flexibility to the fit.

Gown Tag states a USA size 6 , France 38, Great Britain 10, Italy, 42 Deutschland 36.
Bust-34-36"
Waist- up to 30"
Hips-up to 38"
Length-54.5"