The Duchess of Cambridge looked stunning at the event, arriving in a low-back, fitted Alexander McQueen lace gown with sleeves and Erdem earrings. Her husband, Prince William, looked dapper in a black tuxedo.
The couple was greeted with a posy, or small bouquet, and quickly met with the cast of Mary Poppins, who performed later in the evening.
It's been a busy few weeks for the couple, who have participated in Remembrance Day events on behalf of the royal family. Kate also opened a local children's hospice center, The Nook, on Friday, visiting with the children there.
As the family prepares for the holidays with their three children, they will not be joined this Christmas by William's brother, Prince Harry, sister-in-law, Meghan Markle, or nephew, Archie. The Sussexes are spending the holidays with Meghan's mother, Doria Ragland, a Palace spokesperson previously told ET.
A source tells ET that Meghan and Harry are using their holiday break to "recharge their batteries." However, the announcement that the couple intends to spend the holidays with Meghan's mother only reignited speculation about the Duke and Duchess of Sussex's relationship with the royal family. The source disputed ongoing rumors of a rift between Harry and Willliam, saying that just because they are on "different paths doesn’t mean there is a rift."