Kate Middleton played piano with her daughter, Princess Charlotte, in a sweet mother-daughter duet.The surprise moment aired on her Christmas Eve "Together at Christmas" carol service as the opening segment.In the clip, the Princess of Wales sat beside her daughter for a rendition of "Holm Sound" by Erland Cooper.She shared the moment on the @PrinceandPrincessofWales social media page Wednesday.PRINCE WILLIAM EAGER TO DITCH OUTDATED ROYAL CHRISTMAS TRADITIONS AS KING CHARLES RESISTS THE CHANGE: EXPERT"Love and connection through music. A special duet playing Holm Sound by @erlandcooper to open this year's 'Together at Christmas' Carol Service," the post was captioned. "Watch
