Check It. Behind the scenes of 'Mad Men' style.

OK, so we (or I) have been pretty "Mad Men" crazed after their Season 4 premier last Sunday. First we did the pick up lines, then the Banana Republic line and contest, and now this.

Janie Bryant, the costume designer for "Mad Men," takes viewers behind the scenes and explains wardrobe choices behind the show. Why are Don's suits darker this season? What are some of the defining characteristics behind Peggy's clothes? Do they wear period skivvies? (This answer is yes, with a peak at one of Joan's undergarments).

Enjoy!

-- Lauren Williams