The duchess of Cambridge attended the Service of Thanksgiving at St. Paul's Cathedral and a luncheon at Westminster Hall today as part of the Queen's Diamond Jubilee celebration. And she took a ride in a horse-drawn carriage for the first time since the Royal Wedding! For these fun activities, she wore a lace Alexander McQueen dress, a hat by Jane Taylor, and L.K. Bennett pumps. See her full look in our updated Kate Middleton Look Book.