The couple were seen soaking up the festive atmosphere at The Fayre of St. James's in St James's Church, where they enjoyed a magical carol concert and a star-studded evening of performances.
Looking suitably festive in a long wool coat, Princess Beatrice recycled her £1,295 'Halcyon' checked wool-blend twill coat from Temperley London, which she memorably wore last Christmas to the Princess of Wales' Together At Christmas concert last year.
The elevated trench coat features a dramatic collar, waist-cinching belt, and a grey plaid print, which the royal mother paired with towering Louis Vuitton boots and a £570 Movimento mini bucket bag from Mansur Gavriel.
The Princess, 35, stepped into the festivities in LV's £960 'Silhouette Ankle Boots,' one of the luxury fashion house's most emblematic styles. The statement boots boast a flower-shaped heel emblazoned with the LV monogram.
Taking to Instagram style blog @royalfashionpolice, fans were quick to declare their love for the royal's winter ensemble.
"Very sharp looking. The LV accessories complete nicely. Have always loved her sense of style," penned a fan, as another wrote: "She looks fab and that coat is fantastic."
"Olivia Buckingham changed her style game," chimed in a third fan.
Princess Beatrice has been working with the oh-so-chic Olivia Buckingham for the last five years; and many royal fans think the socialite and fashion stylist has transformed the Princess' confidence in dressing.
According to the MailOnline, Olivia previously expressed that "creative freedom" is the key to her sartorial success with clients. "I don’t want it to be one-sided, we meet in the middle and come up with a magical look," she said.
Since working with Beatrice, Olivia's styling partnership with the princess is just as much a friendship as it is a working relationship, with the socialite regularly sharing photographs of the Princess on her personal Instagram.
"We discuss the event and what type of style would work even down to the finer details like jewellery and shoes," she said. "I know that we both believe that if a woman can feel empowered and confident by clothes then that’s what they should be used for."