The trendsetter pulled a fashion switcheroo on Wednesday when she changed from a professional look to casual athleisure midway through the day.
In the morning, Kate hosted Huffington Post UK at Kensington Palace where she served as a guest editor for the outlet to promote Children's Mental Health week. She paired a ladylike white Reiss top with a black and white Dolce & Gabbana skirt for her foray into blogging.
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Kate has supported mental health charities since her 2011 marriage to Prince William, and recently teamed up with Huffington Post UK to launch Young Minds Matter, an initiative exploring the causes and treatment of children's mental health problems.
Chris Jackson / Getty
With reporting by MONIQUE JESSEN