nbcNBC News has landed an exclusive interview with ex-National Security Agency contractor Edward Snowden to air in prime-time on May 28.

"NBC Nightly News" anchor Brian Williams interviewed Snowden in Moscow this week over several hours. He also interviewed Snowden with journalist Glenn Greenwald, who has written a book about Snowden and the trove of documents about the NSA and US government spy programs around the globe.

NBC News' PR unit calls the interview a "rare and revealing in-person conversation" that was "shrouded in secrecy due to Snowden's life in exile since leaking classified documents about US surveillance programs a year ago."

Williams interviewed the duo about how they came to work together and the "global debate sparked by their revelations."