Tom Walker said he has Kate Middleton to thank for making his song "For Those Who Can't Be Here" a hit following their performance on Friday's "Royal Carols: Together At Christmas" at Westminster Abbey.

The Duchess of Cambridge, who hosted the TV program, played the piano while the singer belted out the soft vocals along with his guitar. Talking about the memorable experience, the "What A Time To Be Alive" hitmaker remarked on the positive reviews his track received after their joint performance. He said it "was so well received" and that it "jumped 57 places in the charts."

"It was a wonderful experience and she was so warm. She made the effort to thank all the musicians but it was us who felt so grateful to be part of something so special," Walker shared and joked that he probably owes Kate Middleton royalties now for making his song a hit.

"She sent me a letter thanking me for the opportunity but it should be me thanking her," he told The Sun.

A very special performance of 'For Those Who Can't Be Here' with @IamTomWalker for #TogetherAtChristmas
Watch the full performance on our YouTube channel:

— The Duke and Duchess of Cambridge (@KensingtonRoyal) December 24, 2021

Walker also revealed how he and the Duchess of Cambridge came to collaborate on his track. He said that they met for a rehearsal beforehand and that he sent her "a recording of the track without the piano part so she could practice." He then called the mum-of-three "brilliant" and praised her for the dedication she put into working on the song because it was "obvious she had taken the time to perfect it."

"You think the Royal Family almost don't get nervous, they're so used to the spotlight. But this was obviously a very different, new experience for her," he shared.

It is believed that Kate Middleton came up with the idea to collaborate with Walker after they met at a charity event for Action on Addiction, where he had performed his single "Leave A Light On." As for the royal's performance, fans took to the Facebook page of the Duke and Duchess of Sussex to praise her for being humble and a role model, with one pointing out that she "played as an equal to the other musicians."

Kate Middleton
Kate Middleton, the Duchess of Cambridge Oli Scarff/POOL/AFP via Getty Images