The 33-year-old Duchess of Cambridge, who looked flawlessly regal in a respectful black gown, and William, who opted for a classic tailored suit, wore red Poppy pins to memorialize the nation's soldiers who gave their lives in World War I, and those who have lost their lives while serving their country in the years since.
The couple attended the event, held at the Royal Albert Hall, and sat in a private box along with William's grandparents, Prince Philip, 94, and Queen Elizabeth II, 89.
This year's Festival of Remembrance honored a particularly special milestone, as it marked the 75th anniversary of the Battle of Britain, one of the most significant events during World War II. The famous battle saw U.K. forces victoriously repel Nazi soldiers, but at a great loss of life, both military and civilian.
On Sunday, Kate attended the Remembrance Sunday Service at the Cenotaph on Whitehall war memorial in London. She proved she can look chic even when she's staying somber, wearing a black, double-breasted felt and velvet coat and a black hat with a mesh veil.
William, 33, and his 31-year-old brother, Prince Harry, who have both served in the British military, were joined by the Queen in laying wreaths at the memorial.
Recently stepping out for a lighter occasion, Kate, William and Harry visited the Royal Albert Hall for the London premiere of Spectre late last month. Kate shut down the red carpet in a gorgeous blue gown that is definitely a must-see style.