Robert De Niro has started $1m (�655,000) legal action over a photograph taken at his birthday party.

The alleged paparazzo shot of him and fellow actor Sean Penn blowing out birthday candles was taken at their joint party last year.

Someone snuck into a private residence and took unauthorised pictures for profit

Tom Harvey De Niro's lawyer

De Niro and Penn - who share a 17 August birthday - were holding their 58th and 41st celebrations at a rooftop party at De Niro's loft in New York's fashionable TriBeCa district.

Photo agency Celebrity Vibe tried to sell the photo and it appeared in at least one newspaper and magazine in the US, De Niro's lawyers said.

Lawyer Tom Harvey started the proceedings at Manhattan Supreme Court and insisted the pictures were completely unauthorised.

He said: "Our contention, as we hope to prove in the lawsuit, is that someone snuck into a private residence and took unauthorised pictures for profit."

Penn shares De Niro's birthday

But Jeffrey Boyard, a co-owner of Celebrity Vibe and named specifically in the action, said his agency had done nothing wrong.

"Our photographer was invited," he said.

De Niro won a best supporting Oscar for 1974's The Godfather: Part II and a best actor Oscar for boxing saga Raging Bull.

He has been voted the best actor of all time in a number of polls for a string of classic lead performances including Taxi Driver, The Deer Hunter and King of Comedy.

Penn's starring roles include I Am Sam, Sweet and Lowdown and Carlito's Way as well as directing The Pledge and The Crossing Guard.