The 37-year-old usually plays it safe when it comes to her fashion choices, so of course her daring gown immediately drew comparisons to – which featured a low, scooped back – to the glam look the Duchess of Sussex wore to last year’s performance.
Meghan, who was pregnant with Archie at the time, chose a similar monochrome ensemble by designer Safiyaa, although the mother-of-one's gown had a halter neck top and a white leaf sequin detail.
Meanwhile Prince William - who was looking handsome in a sleek tuxedo - chatted with the West End cast of Mary Poppins who were opening the show for Variety before their opening weekend at the Prince Edward Theatre in London.
The Duke of Cambridge was even overheard saying: "I love Mary Poppins!"
According to Royal correspondent Rebecca English, when Kate was asked why she didn't bring her three children, Prince George, Princess Charlotte and Prince Louis, to the show Kate replied: "They would love it, but not on a school night."