Princess Kate Middleton is ready to show the world her new blonde hair! After teasing a hair transformation during brief sightings over the summer, Kate, 43, officially stepped out with her new look on Thursday, September 4, as she and husband Prince William took in the newly renovated gardens at the National History Museum in London. The Princess of Wales' honey blonde locks were on full display as she wore her hair down for the couple's first royal engagement after their summer break. Kate looked effortlessly chic in a gray blazer, white shirt and black pants.