This was the 30-year-old duchess' first official appearance since leaving a hospital where she was treated for extreme morning sickness and dehydration.
"We're so delighted to be joined by Her Royal Highness the duchess of Cambridge," People.com reported host Gary Lineker telling the audience at the ExCeL arena.
William and Kate married in April 2011 and recently confirmed they are expecting their first child.
Their happy news was marred earlier this month, however, when a nurse who worked at the hospital where the duchess was being treated hanged herself after she was caught up in a radio prank in which she gave out information about Kate's condition to a woman pretending to be Queen Elizabeth II.
2014: The Year in Music [PHOTOS]