Jenner -- who first posed for Calvin Klein in their denim campaign
-- looks at ease in her undergarments and says this sort of modeling comes easy for her. "It was super fun," she tells Women's Wear Daily
of the photo shoot, which also features models Joan Smalls, Isabeli Fontana and Edita Vilkeviciute. "Every girl loves posing in her underwear. It's always fun to do that."