Deep Purple Evening Slip Dress With Buttons

A gorgeous deep purple silky evening dress with a button-up back and spaghetti straps. Size 2 (small) from H&M's Conscious Collection. Waist stretches a little bit, but not much. It's a snug fit everywhere else so please see the measurements below. 

Approximate measurements when flat:

Pit to pit/bust: 14.5inch
Waist: 11inch (stretches to 15inch)
Bottom hem: 26inch
Length (top to bottom): 40inch
Sleeve length: spaghetti straps