Catherine, Duchess of Cambridge, surprised viewers during a televised Christmas Eve carol service by playing the piano during one of the performances. The royal family member, aka Kate Middleton, accompanied Scottish singer-songwriter Tom Walker as he performed his new Christmas song, "For Those Who Can't Be Here."
The video of the performance has been viewed more than 2.7 million times on YouTube. A clip of the song posted on Kensington Palace's official Instagram account has been viewed more than 11 million times.
The concert, dubbed "Royal Carols: Together At Christmas," was organized by Kate to pay tribute to frontline workers and those working to support their communities during the COVID-19 pandemic.
National Health Service employees and representatives from charities were invited to attend the service, which was filmed at Westminster Abbey on Dec. 8 and aired in a television special on ITV in the UK on Christmas Eve.
However, Kate's performance with Walker was secretly prerecorded and only seen during the broadcast.
In an interview with BBC Radio 2, Walker praised Kate's piano playing and revealed how the royal collaboration came to be. The singer-songwriter said he met Kate after performing at a charity event she attended in October. During the planning stages of the carol service, she reached out to him about being involved, he said.
"She asked if I could come down and play at the carol service and I said yeah that’s no problem, but I’ve also written a Christmas song that no one’s heard yet, I can send it over and you can have a listen," he said. "So I sent it over to the team and they absolutely loved it, and then a week later they came back and said, ‘Um, would it be alright if the duchess played along with you?’ and I was like, ‘What?'
"We got together, we rehearsed the song like nine times, and by the end of it she'd absolutely nailed it, and then she went away for a couple of days and practiced it, and then we finally got to do the recording of it," he said in another BBC interview.
"And I was really impressed because it's one thing playing along with me in a studio, just the two of us, but then to jump straight in to playing with a live string quartet and a pianist and two backing singers.
"I think we were both really nervous that it wasn't going to go quite to plan and one of us would let down the other person or whatever, but she was absolutely fabulous — she smashed it," Walker added.
Walker said that the performance was kept so secret that he didn't even tell his own mother about it. "She was in floods of tears watching it on the telly, it was beautiful," he said.
Kate's late mother-in-law, Princess Diana, was also a pianist — while touring a music camp in Australia in 1988, she shocked the press by sitting down at an instrument and playing part of Sergei Rachmaninoff’s "Piano Concerto No. 2" from memory.