Pitt spoke about the unscripted kiss after Robbie revealed that her smooch with her co-star was actually improvised.
Brad Pitt is opening up about his on-screen kiss with Babylon co-star Margot Robbie. ET's Kevin Frazier spoke to the Academy Award-winning actor at the film's premiere in Los Angeles Thursday night where he set the record straight.
"No, not necessarily," Pitt said when asked about Robbie taking a little creative liberty to plant a sneaky kiss on him. "There's always room for character interpretation."
Earlier this month, Robbie revealed to E! News that her smooch with her co-star was actually improvised.
"That wasn't in the script," she told the outlet, "but I thought, 'When else am I gonna get the chance to kiss Brad Pitt? I'm just gonna go for it.'"
While the moment wasn't originally in the script, it did get the OK from the film's director Damien Chazelle beforehand and ended up making the cut.
It wasn't the wildest thing Robbie does in the film either, with Pitt telling ET the Barbie actress was simply "on fire" in the film, which tells the story of how decadence, depravity, and outrageous excess lead to the rise and fall of several ambitious dreamers in 1920s Hollywood.
"Believe me, that's the tamest thing she does in this," Pitt teased of his Once Upon a Time in Hollywood co-star. "She's on fire on this. It's the best I've ever seen her."
In Babylon, Pitt plays on-type as Jack Conrad, one of the biggest movie stars in the world, while Robbie stars as Nellie LaRoy, an unpredictable up-and-coming starlet searching for fame.
Speaking to ET earlier this month, Robbie called starring opposite Pitt a "brilliant" experience.
"It's technically the third film we've appeared in together, and we've never acted together until this film," she shared. "So that was a wonderful gift.... He's so, so wonderful. Watching Brad Pitt, the biggest movie star, play the biggest movie star it's just something like, inherently fun."
As for what Pitt was able to tease about the "big film," he said it makes him to be proud to be a storyteller.
"I mean, there's some good drama in this one. It's really funny and it's big. It makes me really proud to be part of this lineage of getting to contribute to storytelling in my little form," Pitt shared. "And all the people who have come before us and all that'll come after."
Babylon is in theaters Dec. 23.