Prince Harry and Prince William greeted supporters outside of Windsor Castle on Friday, May 18. The royals were all smiles as they shook well wishers’ hands and waved to the crowds. The brothers were touring the castle on the eve of Harry’s wedding to Meghan Markle. “Harry and Meghan are still very excited for Saturday,” a source told Us Weekly. They'll tie the knot at St George’s Chapel in Windsor Castle on Saturday, May 19, in front of 600 guests. Two hundred of those closest to the duo will join them for an intimate evening reception.