A letter WikiLeaks founder Julian Assange sent to Benedict Cumberbatch, urging him to reconsider portraying the exiled journalist in a new film, has been posted on the anti-secrecy website just days before the project hits the big screen.

Assange has been critical of DreamWorks' new biopic The Fifth Estate ever since pre-production began and when the Sherlock star was cast as himself he reached out to the Brit and tried to persuade him to drop the project.

Assange wrote, "I believe you are a good person, but I do not believe that this film is a good film. I do not believe it is going to be positive for me or the people I care about. I believe that it is going to be overwhelmingly negative for me and the people I care about.

"I believe that you should reconsider your involvement in this enterprise. Consider the consequences of your co-operation with a project that vilifies and marginalises a living political refugee to the benefit of an entrenched, corrupt and dangerous state."

Cumberbatch recently told The Hollywood Reporter he had received correspondence from Assange but refused to go into details, stating, "He was pretty keen for me not to do the film, and the rest is sort of between us, really."

Now the letter, which was reportedly sent to Cumberbatch in January (13), has been posted on the WikiLeaks site, alongside a release that reads: "Cumberbatch's reply to this email was courteous and considered. The actor communicated to Assange that aspects of the film's script were troubling to him."

The post also describes the film, which will hit cinemas in the U.S. on 18 October (13), as "fiction masquerading as fact".

Australian Assange is currently exiled at the Ecuadorian embassy in London as U.S. authorities seek to question him over the sensitive and controversial military secrets he exposed online.

The letter posting on WikiLeaks comes just weeks after the leaked script for The Fifth Estate appeared on the whistleblowing website.