The 27-year-old actress denied the romance on Thursday's episode of Watch What Happens Live, but said she wasn't bothered by the speculation.
"No, I've met him once in, like, 2013, so it was very random," she said of the reports. "But, I also wasn't, like, in a huge hurry to debunk it!"
Lawrence was linked to Pitt in December following her split from Darren Aronofsky. She said friend and fellow actress Amy Schumer helped cheer her up in the wake of her breakup with the mother! director.
"When Darren and I first broke up, I told [Amy] and I was really sad," the star recounted.
"The next day I get a bouquet of flowers delivered and I was like, 'What is this?'" she said. "I bring the bouquet of flowers in and there was a note that says, 'I'm so sorry to hear you're gonna die alone. Love, Amy.'"
"I was in love with him for two years," she said. "I still love him very much."
Lawrence will next star in the movie Red Sparrow, which opens in theaters Friday.