Filene's deadstock dark hunter green velvet romper set with sheer long sleeve top NWT and tagged 18M and circa 1996. Seems to run TTS but the inseam length may allow the romper part to fit into 24M.
Measurements are
26.5 inches shoulder to cuff
17 inches shoulder to saddle
10.5 inches pit to pit
7 inches pit to cuff
10 inch inseam