Leonardo DiCaprio won his first Oscar on Sunday, after being nominated four times previously. The actor was expected to win after dominating the best actor race all season, winning a number of precursor awards including a Bafta. Still, he said the industry-wide support he’s received over the past few months “feels incredibly surreal”.

“This year in particular I was overwhelmed by the support from fans and people in the industry,” he said backstage at the ceremony, shortly after winning his best actor Oscar for The Revenant. “I’m grateful, I really am.”

DiCaprio took time to reminisce about his time spent growing up in east Los Angeles, “very close to the Hollywood studio system”.

“I felt detached from it my whole life,” he said. “But to have parents who allowed me to be a part of the industry, and to be able to tell stories like this, has been a dream for me since I was four years old.”

Speaking of The Revenant, DiCaprio called the survival thriller, which lost out on best picture to Spotlight, “exemplary”. Its director, Alejandro González Iñárritu, won the Oscar for best director.

“This was a journey that I’ll never forget with Alejandro,” said DiCaprio. “It took up such a large part of our lives, but as a result we have a great film to look back on for years to come.”

DiCaprio, who also heads the Leonardo DiCaprio foundation, “dedicated to the long-term health and wellbeing of all Earth’s inhabitants”, used a large portion of his acceptance speech to urgently address his cause.

Asked to elaborate on his comments, DiCaprio said: “To not only talk about the film, but to be able to talk about climate change on a platform that hundreds of millions of people are watching … to say this is the most existential crisis our civilisation has ever known – I wanted to speak out about that. The time is now. It’s imperative we act.”

“I feel there is a ticking clock, there is a sense of urgency that we all must do something pro-active about this issue,” he added. “Certainly with this upcoming election, the truth is this: if you do not believe in climate change, you do not believe in modern science or empirical truths – and you will be on the wrong side of history. We need to all join together and vote for leaders who care about the future of this civilisation.”