Prince William 's younger brother will be his best man when he marries Kate Middleton . Middleton 's sister Philippa will be her maid of honor . Arrange the `` stag '' or bachelor party • Assist the groom with choice of outfit • Pick-out the ushers ' outfits with the bride and groom • Collect and return any hired formalwear • Act as intermediary between the groom and ushers and ensure they know what elements of their outfit they will need to provide , or are expected to wear , Score: 7 William is second in line to the throne .
Prince William 's younger brother will be his best man when he marries Kate Middleton . Middleton 's sister Philippa will be her maid of honor . Score: 7 William is second in line to the throne .