Oh, Betty! Only a select few can pull off the no-underwear look and still look classy, elegant, and sexy as hell. January Jones is one of those women.Her appearance on The Tonight Show with Jimmy Fallon last Friday, March 28, has left people buzzing. Her revealing black jumpsuit showed off a lot of skin with its cut-out design that goes down her legs. Check out her hotness in action with a clip from the show below!