Jessica Chastain -- Kurt Busch Is Wrong ... Ex-GF Was NOT Real 'Zero Dark Thirty' Hero (VIDEO)

Jessica Chastain is shooting down Kurt Busch's conspiracy theory about his ex-girlfriend -- claiming her character in "Zero Dark Thirty" was ABSOLUTELY NOT based on Patricia Driscoll.

Remember, during their 2015 domestic violence case ... Busch testified that he believed Driscoll was a trained assassin for the U.S. government ... and that she had claimed Maya from "ZD30" was partially based on her.

So, when we got Jessica Chastain out at Baltaire restaurant in L.A. Monday night -- we had to ask her to set the record straight once and for all.

"It's not true," Chastain told us ... "On my life, no."

So, there you have it -- unless that's what the government WANTS you to think!!

For her part, Driscoll has denied being a super assassin.