According to royal tradition, royals should always wear hats or a headpiece in public until 6pm. After this point, married women should swap their hats for a tiara. However, royal women who are unmarried are not allowed to do this – even if they are royal or engaged. Once married, women are immediately able to wear their first tiaras – even as soon as their actual wedding days. As many will recall, Kate wore her first tiara during her wedding to Prince William, despite royal etiquette that suggests tiaras are worn for evening use only.

Source: Daily Mirror March 14, 2022 22:30 UTC