Well, who said that white-ties and jewels should be worn only for State visits or top-level gala concerts?
King Philippe's and King Willem-Alexander's British cousin has less restraint when she attends concerts, even variety ones: she is the Queen, so she displays her bling! Well done, Ma'am!
Caption: Royal Variety Performance at the London Palladium in 1967 - Queen Elizabeth II in the Royal Box (Daily Mail/Rex / Alamy Stock Photo)