Julian Assange refused to meet Benedict Cumberbatch while he was preparing to play the WikiLeaks founder on film.
In the letter, sent in January, Assange described Cumberbatchs film, The Fifth Estate, as "toxic" and "distorted".
He also urged the actor: "Reconsider your involvement in this enterprise".
The Australian whistle-blower has been living at the Ecuadorean embassy in London after claiming asylum a year ago to avoid exile to Sweden.
