Prince William's cousin, 36, arrived at Westminster Abbey in a gorgeous burgundy dress with a delicate floral print and a floaty midi skirt that skimmed over her blossoming baby bump.
WATCH: Princess Kate Looks Festive In Red As She Arrives For Christmas Carol Service
The royal's dress in the colour of the season was teamed with a red bag and a plum-coloured jacket layered over her shoulders to keep the cool air at bay.
For shoes, the expectant mother opted for velvet pointed-toe heels which complemented her tonal ensemble effortlessly.
Sarah Ferguson's eldest daughter wore her lovely auburn locks in tumbling curls that fell past her shoulders and her makeup look featured long lashes and a soft berry lipstick.
Princess Beatrice has attended Kate's carol service since its first year in 2021 to pay tribute to those who supported their communities through the COVID-19 pandemic.
The Princess wore a gingerbread-hued collarless coat dress from The Fold with a pair of midnight blue velvet platform heels by Jimmy Choo and a deep red croc print 'Hat Box' bag by Aspinal of London.
The Princess previously commanded attention when she stepped out on Christmas Day alongside all her royal family members for the church service at Sandringham.
Last year, Beatrice arrived at St Mary Magdalene Church wearing a navy belted coat with a statement floral headband in the same hue.