Both of Diana's sons and their wives often honour the late princess in both style and actions. Meghan took this very seriously, choosing a cause dear to Diana's heart as her first royal charity appearance. In December 2017, Meghan and Harry made their first philanthropic outing as an engaged couple to the Terrence Higgins Trust World AIDS Day Charity Fair in Nottingham. AIDS research was one of Diana's signature causes, particularly in the 1980s and '90s when knowledge about the disease was sparse and fear was high.