Jane Birkin, from the pages of Vogue UK March 1972. Ever since dressing as a Pierrot for Halloween, I've become a little obsessed with the costume (and the idea of someday trying it again, only with more prep time and attention to detail.) She makes an awfully chic Pierrette here, and in Dior to boot!
I found this image over on Youthquakers, one of my very favorite sites to browse. It reminds me of the time I spent on Work-Study at McHenry Library at UCSC, not-so-subtly sneaking off during my shift to pour over their huge collection of hard-bound vintage US Vogue magazines. I still have stacks of the pages I photocopied, Veruschka and Marissa and Penelope et al.