Hope this helps! but, I have a babydoll shirt just like this one just a different design (babydoll) is what it's called :) I'm a little top heavy and I usually wear a supportive sports bra with these types of blouses because with a typical bra they become very revealing but if this is a stretchable material as stated this would fit a large but may be a bit form fitting! as far as my blouses like this a shirt underneath is usually not necessary! I LOVE these tops, & this is a great auction!