Actor Jonah Hill has apologised hours after a video emerged showing him using a gay slur to a paparazzo.

The video posted by TMZ shows a photographer pestering Jonah, who eventually responded with muttered expletives and an anti-gay expression.

Later, on The Howard Stern Show, the 30-year-old Wolf Of Wall Street star acknowledged that he said "a disgusting word".

Jonah said the word "does not at all reflect how I feel about any group of people" and he had been a gay-rights activist "from the day I was born".

Earlier this year Jonah promoted a Human Rights Campaign effort opposing anti-gay laws in Russia ahead of the Winter Olympics.

He said he had been harassed by the photographer, claiming he said "hurtful things" about Jonah and his family.