Elisabeth Moss did a lingerie photo shoot for GQ, and was unable to remove Peggy Olsen's sad office cardigan (and blazer) the whole time. Do photo editors not trust us to recognize her without office clothes or something? In her only other lingerie spread to date, Moss wore panties with a trench coat:
Other explanations: Elisabeth Moss is a never-nude; Elisabeth Moss is hiding an "outie" belly button; Elisabeth Moss is hiding a giant tramp stamp that says I'M SO SICK OF PEGGY OLSON; Elisabeth Moss is genius who has discovered a foolproof method for getting the lad-mag exposure she needs for her career without actually exposing herself.
I hope it's the tramp stamp.