The curvaceous 35-year-old's raunchy past was exposed on the magazine's Twitter page, when a representative uploaded an image of her posing with two other models in silver bikinis and blonde wigs from a past edition.
The unknown poster asked on their profile: "Who is the famous actress in this photo from the July 1999 issue? For those who guessed Christina Hendricks from Mad Men, way to go! She's on the right and helped illustrate an article on summer shooters."
WENN writes that in one "bizarre" shot, Hendricks can be seen "straddling a heavily-tanned man in small swimming shorts, while a wild-haired clown appears in the background".
Hendricks recently declared that she is "thrilled" to be seen as a sex symbol.
