The royal couple, who left Prince George, 6, Princess Charlotte, 4, and 1-year-old Prince Louis back home at the palace, attended the annual Royal Variety Performance at the Palladium Theatre in London on Monday evening. The event supports the Royal Variety Charity, of which the Queen is patron. The money raised from the show helps hundreds of entertainers throughout the U.K., who need help and assistance as a result of old age, ill-health or hard times.
Kate wore a black lace gown by Alexander McQueen (her wedding dress designer!) paired with dangling Erdem earrings, while William looked dapper in a classic black bow tie.
On the way in, they chatted with some of the cast of Mary Poppins in London. Kate told singer Petula Clark that her kids had asked if they could come to the musical event, but that Kate had told them, “Not on a school night!”
The event will include performances from the cast of Mary Poppins, Lewis Capaldi, Mabel, Robbie Williams, the cast of Come From Away and a special collaboration by Emeli Sandé and Manchester’s Bee Vocal choir.
The show was hosted by comedian Rob Beckett and Ramesh Ranganathan, who jokingly introduced the royal couple and teased them that they were on a “date night.” As the camera focused on them laughing in the Royal Box, William nodded with mock seriousness.
The comedians asked whether they had paid the babysitter to stay “until 12 or 1” – joking: “It’s always worth £20 for the extra hour.”
The royal couple also laughed when Ranganathan said he, like the Cambridges, had three children and guessed that William and Kate thought the same thing when they saw their three little faces running into their bedroom each morning: “Why did we do this?”
William and Kate, who celebrated the ninth anniversary of their royal engagement over the weekend, will meet with some of the performers and charity members before and after the show.
Last year, Meghan Markle and Prince Harry attended the event on behalf of the royal family. But they are currently on a six-week break from their royal duties to spend some valuable “family time” together, a royal source confirmed to PEOPLE.
The origins of the Royal Variety Performance date back to 1912 when King George V and Queen Mary agreed to attend a “Royal Command Performance” at the Palace Theatre in London, in aid of the Variety Artistes’ Benevolent Fund. In July 1919, the second royal show was performed and was the first to be billed a “Royal Variety Performance.”
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Held at London’s Coliseum, the show was staged as a “celebration of peace” and, as the official announcement expressed it, “had been commanded by The King to show his appreciation of the generous manner in which artistes of the variety stage had helped the numerous funds connected with the war.”