Better get the boys to help you guess who this white-hot actress is ... if you don't already recognize her bodacious bosom. Trust us ... when you figure out who the beautiful babe in the white dress ...

It's Guess Who time ... and here we've got a sexy A-List actress who is using nothing more than her hands to cover her breasts in a NSFW selfie!!! We'll give ya one hint because we know you're dying ...