Barack Obama and actor Leonardo DiCaprio have joined forces to call for action to combat climate change.
The pair spoke about the issue in front of a crowd at the White House attending the South by South Lawn festival.
The US President said the world faces "a race against time" to stop climate change, saying efforts so far were "incomplete" but that "we can still pass the test".
Presidential candidates Donald Trump and Hillary Clinton were not mentioned in the discussion, but Oscar winner DiCaprio made a thinly-veiled reference to the former.
DiCaprio, who supports Mrs Clinton's campaign, said the scientific consensus about the dangers of climate change was in and "the argument is now over".
He added: "If you do not believe in climate change, you do not believe in facts or in science. And therefore, in my humble opinion, you should not be allowed to hold public office."
Mr Trump has previously referred to climate change as a hoax.
DiCaprio recently completed a documentary film about climate change, Before The Flood, which had its domestic premiere on the White House lawn after the discussion.