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.

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“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 Royal Carols: Together at Christmas on ITVX now.”

“At its heart, Christmas speaks of love taking full bloom in the simplest, most human ways,” the mother of three is heard saying in the Instagram clip.

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Princess Kate wore a dark blue gown and Princess Charlotte wore a plaid skirt with a blue blouse.

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“Not in sentimental or grand gestures, but gentle ones, a moment of listening, a word of comfort, a friendly conversation, a helping hand. Presence. These simple acts of care might seem small, but they contribute to the beautiful tapestry of life to which we all belong,” she added.

In the clip, Princess Charlotte was joined by her siblings Prince George and Prince Louis adding Christmas decorations with their names handwritten on them, onto the tree located outside of Westminster Abbey.

Princess Charlotte, Prince George and Prince Louis all coordinated in dark blue and white accented looks.

Prince William wore a dark blue suit and Princess Kate opted for a dark green calf-length coat.

She ended the clip by wishing everyone a “very happy Christmas.”

The clip is part of the “Together at Christmas” special.

The footage included also shows guests arriving for the service, which took place on Dec. 5 at Westminster Abbey.

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