The film stars Naomi Watts as real-life CIA officer Valerie Plame, while Piper Perabo plays fictional CIA trainee Annie Walker in Covert Affairs.
Liman explained to Zap2It that the new show has benefited from the research he carried out for Fair Game.
"Most of the material that we were learning about had no place in the movie, unless I wanted the movie to be ten hours long," he said. "[It] was just like the perfect timing to be developing a TV show in the same arena at the same time.
"By far the most interesting aspect of the spy world that I got exposed to during all the research for Fair Game is what happens when spies go home, and where spies intersect our world".
He explained that Covert Affairs will be grounded in reality and will not glamourise the spy world.
"What's honest about this show is that when she's in the office, she has to go and get the coffee, because she's the lowest level employee. [Just] because it's the CIA, it's still a business. And it's still a bureaucracy. And there's still all of the stuff that the rest of us have."
Liman previously insisted that the casting of Perabo was critical to the show's success.
Covert Affairs premieres on July 13 at 10pm on USA.
> Click here for our Cannes review of Fair Game