Laura Poitras’s Edward Snowden documentary “Citizenfour” has been added to the line up of the upcoming London Film Festival (Oct 8-19). It will be given a special presentation on Oct. 17 and 18.

The film charts the meeting between Poitras, who was already working on a film about national Security, and her meetings with whistleblower Edward Snowden in Hong Kong, at a time when Snowden was being hunted by U.S. security operatives.

LFF director, Clare Stewart called the film “hugely significant.”

The film is executive producers by Steven Soderbergh, David Menschel, Jeff Skoll, Diane Weyermann, and HBO’s Sheila Nevins. It will play on Oct. 10 at the New York Film Festival.

It will be released in U.K. theaters by Artificial Eye and BRITDOC Foundation on Oct. 31 as a Film4 co-production. Channel 4 will play the film on TV in early 2015.