Musician shares the cheeky way he greeted Princess Kate when they performed together

Three years later, the 31-year-old Scotsman has been asked how he addressed the royal.

Walker quipped: "I can't recall if I'm honest, it was probably 'Alright mate'?"

The singer reflected on his poignant performance with Kate for the "Royal Carols: Together At Christmas" service, taking place just before the UK entered another lockdown.

Walker and Kate, 42, played a moving rendition of his song "For Those Who Can't Be Here" by candlelight.

The performance was a closely guarded secret, with Walker unable to tell even his parents until shortly before the event.

Walker described the experience as "amazing" but not something he "really expected to do" during his career.

The singer was first approached for the carol service in October 2021, after Kate heard him perform at a charity event.

The princess then suggested accompanying him on the piano, as music had brought her "great comfort" during lockdowns.

Walker continued to tell Good Morning Britain: "It was kind of a big top secret, I found out like a month before it happened and then we did a top-secret rehearsal. You should have seen my Gran's face when she saw it on the telly, she couldn't believe it."

Due to Covid restrictions, the pair had to rehearse on opposite sides of the room.

Walker previously told The Mail the whole plan was "very, very secret", and they were both nervous about potentially making mistakes.

He praised Kate's musical abilities, describing her as an "amazing musician". Despite initial nerves during rehearsals, he noted her dedication to perfecting the performance.

"She went away and invested a lot of time and energy into getting it right," Walker said.

The singer provided Kate with a backing track to practise and was impressed by her improvement. "I was shocked at how much better she was when it came to the actual show," he remarked.

Walker emphasised the uniqueness of the experience, calling it "truly an honour" and "a once-in-a-lifetime experience".

He commended Kate's professionalism, stating: "It's not easy to just jump behind a piano with a bunch of musicians you've never played with before and record live takes to camera, but she completely nailed it."

Reflecting on his performance with Princess Kate, Walker told The Mirror in 2023: "I think that was her one and only gig and possibly song, I'm not sure she's planning on making a career of it."

He reiterated his admiration for Kate, describing her as a "lovely, kind and warm-hearted person" who "absolutely smashed" the performance.