Julian Assange has hit out at a Hollywood film about his secret-spilling website WikiLeaks, calling the movie "a massive propaganda attack", according to AFP.

Speaking to students at Britain's prestigious Oxford University by video link from the Ecuadoran embassy in London, Assange revealed that he had acquired a copy of the script for The Fifth Estate, due to be released in November.

"It is a lie upon lie. The movie is a massive propaganda attack on WikiLeaks and the character of my staff," Assange said to the university's Oxford Union debating club.

Assange also blasted the movie for implying that Iran was working on a nuclear bomb. Reading from the script, he said the opening scene was set inside a military complex in Iran with documents containing nuclear symbols. "How does this have anything to do with us?"

DreamWorks Studios announced on Tuesday that it had begun shooting the WikiLeaks movie, which stars British actor Benedict Cumberbatch as Assange.

A photo released by the company showed Cumberbatch with hair dyed the same platinum shade as the WikiLeaks founder's, with German actor Daniel Bruehl standing beside him as former WikiLeaks spokesman Daniel Domscheit-Berg.

"The Fifth Estate traces the heady, early days of WikiLeaks, culminating in the release of a series of controversial and history changing information leaks," DreamWorks said.

Bill Condon, who directed the final two instalments in the Twilight vampire saga, said the movie "won't claim any long view authority on its subject, or attempt any final judgment".

"We want to explore the complexities and challenges of transparency in the information age and, we hope, enliven and enrich the conversations WikiLeaks has already provoked," Condon said.

The Fifth Estate will be in U.S. cinemas from November 15.