Prince William used a speech during a pop concert Saturday night to issue an urgent call for action on the environment. Speaking at the Platinum Party at the Palace in London, held to mark the queen’s 70-year reign, William spoke after a film clip focusing on environmental issues spearheaded by the great British naturalist Sir David Attenborough was projected on the walls of Buckingham Palace. He said that the planet “has become more fragile,” adding, “The pressing need to protect and restore our planet has never been more urgent.” William said he was, like his grandmother, “an optimist,” and that he was encouraged that “environmental issues are now at the top of the global agenda.” He said: “Together, if we harness the very best of humankind, and restore our planet, we will protect it for our children, for our grandchildren and for future generations to come. They will be able to say—with pride at what’s been achieved—‘What a Wonderful World’.”

Another notable moment came when Prince Charles took to the stage to thank his mother for her service, beginning his speech by saying, “Your Majesty,” followed by a long and dramatic pause before he added, wryly, “Mummy.”