WATCHING MARY-KATE AND ASHLEY OLSEN pose for a photo shoot is like watching a hypnotic piece of performance art. Former child stars, extraordinarily savvy brand nurturers, founders and owners of an estimated $1.5 billion business empire and, now, designers of the critically acclaimed high-end fashion line The Row, the Olsens have spent the great majority of their 26 years either in front of a camera or otherwise hard at work. Veterans of fields in which "consummate professional" is a vastly overused term, these two women know exactly what they are supposed to do. And they do it perfectly.

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