Popsugar Celebrity The Royals Prince William and Kate Middleton Halloween Costumes 10 Ways You and Your Partner Can Be Prince William and Kate Middleton For Halloween 11 August 2018 by Kelsie Gibson View On One Page Photo 7 of 10 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 7 Royal Ascot Kate and William What to wear for Kate: a white lace dress and a matching hat. What to wear for William: morning dress, complete with top hat. Previous Next Start Slideshow The RoyalsHalloween Costumes 2018Couples CostumesPop Culture Halloween CostumesThe British RoyalsHalloweenPrince WilliamKate Middleton