Vintage 80’s prom dress

Vintage 1980s strapless shiny purple floral metallic over velvety black material prom dress by Georgio Sant'Angelo. Acetate slip and tulle skirt underneath. Size not labeled - estimated size XXL, please see measurements as this is just an estimate. I am size 18 and it fit but could also fit size 14 and 16 due to elastic “tube top”. Good vintage condition!! Measurements taken across front laid flat 16" across front armpit to armpit-stretches to 24" 20" across front of waist - stretches to 24" 49" length armpit to bottom