black long sleeve dress fit and flare boohoo Women's Wide Rib Maxi - on closure offers easy wear Ella Fit & Flare Dress

Perfectly designed to complement an evening gown, it drapes beautifully over the shoulders, adding a touch of sophistication to any formal look

The company's vice president said it was "most iconic piece of pop culture that there is"

do not hang solely by the spaghetti straps to prevent stretching the bodice

Wide Brim Stripe Trim Cowgirl Hat A wide brim hat is perfect for adding a touch of cowgirl chic to any look

The flirty frock was worked on with Jenners stylist Monica Rose, and the dress, which is rumored to have cost $9,000, conjured up throwback images of another It girl celebrating her 21st birthday back in 2002: Paris Hilton