"No sex!" Lawrence, 24, quipped to reporters at the Cinema Society's New York City premiere of Serena on Saturday.
Serena is the real-life BFFs' third film together, after Silver Linings and American Hustle. And it was Lawrence who recruited Cooper, 40, for the period piece.
"I forced him to come onto the movie," said Lawrence. "I mean, any male role is going to make me think of Bradley because in my opinion, he's the best, and I love working with him."
For the newly single Cooper, the feeling's mutual.
"I respect her so much as a professional, as an actor, and I think she's the best there is," he said. "And I just learn from her. You always want to work with people that are better than you."
The pals said they rarely disagree on anything – especially food.
"Never about where to go to dinner; we're both two of the biggest eaters in Hollywood," she joked at the screening that evening, which was hosted by Dior Beauty and Belvedere.
Lawrence – who's dating Coldplay rocker Chris Martin – is reuniting with Cooper and their Silver Linings and American Hustle director David O. Russell on the upcoming biopic Joy.