Princess of Wales leads royal Christmas walk with Prince William and their children, showcasing family unity while greeting enthusiastic public crowds at service.

Historically, there is precedent for royal women wearing tiaras before marriage. Princess Margaret wore the Cartier Halo tiara to a state banquet in 1956, four years before her wedding. Anne herself was photographed wearing a tiara as a teenager, long before her 1973 marriage to Captain Mark Phillips.

Whereas her other December 25 ensembles played it relatively safe, this particular look threw caution to the wind.