The 35-year-old actress, who divorced her ex-husband Tom Sturridge in 2015, says she will not dignify the reports by reacting to it, reported New York Post Page Six.
When asked about it, Miller laughed off the suggestion, saying, "I'm not going to even dignify it with a response. It's predictable and silly."
Pitt's production company Plan B is behind Miller's latest film "The Lost City of Z", and he and Miller were reported to have been "heavily enjoying each other's company" and "talking to each other all night" at a dinner for the film the previous evening.