The beautiful singer was picture leaving the ITV studios in central London on Monday (9 March) after an interview on Lorraine where she spoke about her recent visit to China to sing for the royal.
"I got to sing for Prince William and he said his favourite song is 'Backtrack' and he loves listening to that in the morning which was lovely," she said.
"I didn't know he knew who I was. I was like, 'Really? You listen to my music? Really? That's lovely!'"
Rebecca said she felt "honoured" to have been chosen to visit China and sing for the prince, saying she'd become tearful before going on stage as it was all so overwhelming.
It's hard to believe it was five years ago that Rebecca finished runner-up on X Factor behind Matt Cardle and in front of One Direction.
"It's been amazing," she said. "I look back and I feel I was a different person then. I was so shy. It's just so crazy to look back."
Rebecca is currently promoting her new album, Lady Sings The Blues, inspired by the songs of Billie Holiday.
"She's somebody who had the worst life story in the sense she had to overcome a lot. She inspires me because of that. She still got up on that stage and sang and sang so well. She was a proper trooper."
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