Bust out the champagne and cupcakes and join us in wishing Kate Middleton a happy (belated) birthday! That’s right—yesterday was the Duchess of Cambridge’s 37th birthday, and according to ‘The Daily Mail,’ Kate passed on an extravagant party and instead chose to celebrate with her husband Prince William, and their three children, George, Charlotte, and Louis. Prince William did have to spend part of his wife’s birthday doing charity work.