Prince Harry urged teenagers to "look up" from their smartphones and go out and change the world at a surprise appearance at a youth event in Toronto.
The Prince criticised clickbait culture and fake news in his speech to thousands of teens gathered for the WE Day convention.
He told the crowd: "In today's world too many people feel cynical and apathetic.
"I get that the challenges we face sometimes seem complex and even scary, especially when we don't know who to turn to for answers.
"I know that while this generation of young people wants to make our world a better place, you often struggle to get your voices heard.
"I know that you, more than any previous generation, care deeply about the health and sustainability of the planet you're going to inherit.
"And I see that you're frustrated, that entrenched mindsets are not keeping pace with the urgency of the threats to our environment.
"But today you are all saying no to pessimism and cynicism."
The WE Movement says it "brings people together and gives them the tools to save the world".
The Prince, who is in Toronto for the Invictus Games for disabled veterans, told the audience to listen to the competitors' stories and the challenges they have overcome and "let yourselves be inspired".
"The thousands of you gathered here are proof that today's generation is the most connected, most energised and most confident the planet has ever known," he said.
"You know that in a clickbait culture, we cannot waste time sharing and drawing attention to things that make us angry, or that we know to be false.
"You all know that it's great to 'like' things on social media, but that it's more important to look up from our phones, to get out into our communities, and to take real action - to stand up for what you believe in."
He vowed to do everything he could to create a platform for young people to get their ideas heard.