Carole, 68, appeared to take a leaf out of her eldest daughter Kate's style book in a striking velvet ensemble.
The businesswoman teamed her black high-waisted flares with a matching top and a double-breasted cropped blazer from Great Scot.
She completed her ensemble with a pillbox clutch bag and pair of suede court shoes.
Carole kept her accessories simple, with the addition of some pearl earrings.
Her brunette locks were styled in a straight blow dry with flipped ends and she opted for a bronzed makeup look.
The Middleton matriarch typically opts for tailored coats or colour block dresses, but she jumped on the velvet trouser trend for the outing.
Carole's husband Michael, 74, looked smart in a blue suit and a patterned tie.
Meanwhile, the couple's eldest daughter Pippa Middleton, 40, rocked a tweed suit from Saloni as she attended the festive event in London with her husband, James Matthews.
Pippa and James are parents to three children – Arthur, Grace and Rose – who were not in attendance.
Extended members of the royal family were also among the guests, including the Duchess of Edinburgh, Princess Beatrice and Edoardo Mapelli Mozzi, Princess Eugenie, Zara Tindall, Peter Phillips and his daughters, Savannah and Isla.
This year the service reflected the Princess of Wales's early years Shaping Us campaign launched in January, which aims to highlight and promote the significance of the formative years of a child’s life.
It was billed as a moment to thank all those who work to support babies, young children and families in communities across the UK and among the 1,500 guests were midwives and nursery teachers.
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