William, in RAF uniform, was one of the senior royals making a somber commemoration of those who have died in the World Wars and other conflicts on Remembrance Day.
He followed his grandmother Queen Elizabeth and her husband Prince Philip in laying a wreath of bright red poppies at the Cenotaph in Whitehall, London.
Kate, whose coat was decorated with poppy-style jewelry, watched from a balcony along with William's Aunt Sophie, Countess of Wessex.
The royals traditionally lead the commemorations in London, where hundreds of veterans then paraded. At 11 a.m. around the U.K., the country fell silent for two minutes of reflection.
Missing this year was Prince Harry, who is currently on a military tour in Afghanistan.