The Duke and Duchess of Cambridge were watching a film premiere about the life of Nelson Mandela when news of the former South African president's death broke.
William and Kate were watching the UK and European premiere of the film Mandela: Long Walk To Freedom at the Odeon Leicester Square in London as part of the Royal Film Performance.
William said after the film: "It was extremely sad and tragic news.
"We were just reminded of what an extraordinary and inspiring man Nelson Mandela was and my thoughts and prayers are with him and his family right now."
The film's cast, including British actor Idris Elba, who played Mandela, and Naomie Harris, who played his ex-wife Winnie Mandela, were also at the premiere.
Tragically, his daughter Zindzi Mandela was also at the red carpet event and unwittingly told reporters her father was doing well.
"My father is fine," she said.
"He's 95 years old and he is pretty frail. We are hoping to see more of him."
Ms Mandela said she had approved of the clips of the film she had seen so far. "I love it. I think it's authentic," she said.
Video: Zindzi Mandela speaks about her father