DiCaprio joins UN campaign

Leonardo DiCaprio will address world leaders at a United Nations climate summit next week as the new "UN messenger of peace" with focus on climate change, the UN chief said on Tuesday.

The star of the hit films Titanic and The Wolf of Wall Street has been vocal on the need for action on global warming through his "Leonardo DiCaprio Foundation".

"I feel a moral obligation to speak out at this key moment in human history - it is a moment for action," DiCaprio said in a statement.