The two-part political drama stars Daniels opposite Brendan Gleeson as U.S. President Donald Trump, and chronicles tensions between the pair during the real estate mogul-turned-politician's first few months in the White House.
Comey was fired by the controversial leader in 2017 after investigating possible ties between Trump's presidential campaign and Russian authorities, and he subsequently wrote about the saga in his book, "A Higher Loyalty: Truth, Lies and Leadership", on which "The Comey Rule" is based.
Daniels reveals he only met Comey after cameras had already started rolling on the show, as the lead actors reenacted a private meeting between the main characters in January, 2017 - when Trump appeared to demand the FBI chief's loyalty and then reportedly threatened to have him removed from the high-profile job.
The pivotal scene was played out so perfectly onscreen, Comey was left feeling physically ill.
"He saw it and he was emotional...," Daniels recalled on U.S. talk show "The View".
"Jim Comey was sitting off camera, that was the day I met him, two months into shooting, and he came round the corner and said, 'Well, you brought it all back: the emotions, the uncomfortableness, the inappropriateness of what I was being confronted with, how I was gonna respond, (how) my mind was worrying. I feel a bit nauseous, to be honest'."
Joking about the comment, the "Dumb and Dumber" star added, "Usually when you tell an actor that their performance made you nauseous, it's not a good thing, but in this case, it was!".
"The Comey Rule", adapted and directed by Captain Phillips screenwriter Billy Ray, premieres in the U.S. on Sunday, September 27.