Prince William dances to “Shake It Off” at Taylor Swift concert

Prince William showcased his dance moves while attending Taylor Swift's "Eras" tour concert in London with children Prince George, 10, and Princess Charlotte, 9.

Originally appeared on E! Online

Prince William was dancing like nobody was watching at Taylor Swift's London concert.

That is, if "nobody" was the some 90,000 fellow fans at London's Wembley Arena. While watching the singer's "Eras" tour show from a VIP box with kids Prince George, 10, and Princess Charlotte, 9, June 21, the Prince of Wales danced to "Shake It Off" and a fan's video of him showcasing his moves has gone viral.

Prince William, who was celebrating his 42nd birthday, and the children got to meet Swift in person as well. He and the "Blank Space" singer shared photos of themselves taking selfies backstage, with the Grammy winner including her boyfriend Travis Kelce in her pic, making their relationship Instagram official less than a year after they began dating.

"Happy Bday M8!" she captioned her post. "London shows are off to a splendid start."

The Prince, who famously performed with Swift and Jon Bon Jovi at an event in Kensington Palace in 2013, captioned his pic, shared on his and wife Kate Middleton's Instagram page, "Thank you @taylorswift for a great evening! #LondonTSTheErastour."

Britain's Prince William, Duke of Cambridge, (R) sings with US singers Jon Bon Jovi (C) and Taylor Swift (L) at the Centrepoint Gala Dinner at Kensington Palace in London, on November 26, 2013. Dominic Lipinski/AFP via Getty Images

Princess Charlotte's Cutest Photos

The Royal Family outing comes less than a week after the Princess of Wales joined her husband and kids, including youngest son Prince Louis, 6, at the annual Trooping the Colour parade, a celebration of King Charles III's birthday. It marked her first in-person public appearance since last Christmas and took place almost two months after she revealed her cancer diagnosis. She is still undergoing treatments.

On June 14, she shared an update on her health battle, saying on Instagram she hoped to "join a few public engagements over the summer, but equally knowing I am not out of the woods yet."

The princess said she was undergoing chemotherapy and was "making good progress," adding that her "treatment is ongoing and will be for a few more months."

Prince William, the couple's eldest kids and Travis were not the only celebs spotted at Taylor's London concert. Also seen at the show: the athlete's brother Jason Kelce and his wife Kylie Kelce, Bridgerton's Nicola Coughlan, Queer Eye alum Jonathan Van Ness, Leslie Mann and Cara Delevigne.