It must be our lucky week, because Kate Middleton just stepped out for another royal appearance. After showing off her sporty side during a Coach Core event with Prince William on Tuesday, the mother of three made a special visit to the Imperial War Museum in London on Wednesday. The duchess looked absolutely stunning in a royal blue dress as she mingled with the director of the museum outside. Inside, Kate was given a special surprise as she viewed letters about three brothers of her great-grandmother, all of whom fought and died in World War I. Kate's great-grandmother, Olive, worked as a nurse during the war and corresponded with her brothers, Francis, Maurice, and Lionel, during their time in the trenches. See more gorgeous photos from her outing ahead.