'X-Men: First Class': January Jones' Sexiest Emma Frost Moments (PHOTOS)

January Jones knows a thing or two about cold characters: her Betty in "Mad Men" is as uninviting as they come, and in the new "X-Men" movie, her Emma Frost actually harnesses the power of telepathy and mind control.

Curious, then, why she wears so little clothing.

A large part of Fox's advertising campaign for "X-Men: First Class," the 60s-set prequel that's garnering rave reviews, has been showing off Jones in as little clothing as possible, from trailers to promo shots. We've gathered the best (or, least clothed) images from that campaign and put them in one handy place.

The movie marketing, by the way, seems to be working; the film took in $21 million on its first day in theaters and is on track to meet its estimated $55-million first weekend goal.