The 40-year-old actress confessed in her memoir, Unqualified, which was published Tuesday following her split from Pratt, that she "couldn't" ignore reports about the actor and Lawrence, who co-starred in Passengers.
"Before they met in person, my publicist, out of the blue, pulled me aside," Faris recounted in the book. "'Anna, listen there are going to be paparazzi all over them,' she said. 'There are going to be shots of them laughing together on their way to set. There are going to be stories circulating, and you have to brace yourself for this.'"
"Jennifer and I are really friendly, and she was apologetic even though she didn't need to be because she hadn't done anything wrong," she added, according to Us Weekly.
Faris said the speculation about Pratt and Lawrence was "totally hurtful" and left her "insecure," despite her relationship with the younger actress. She tried to ignore the rumors but admitted, "I couldn't block them out, either."
"It's hurtful and embarrassing ... even if it's patently untrue ... you still feel and, look like a fool," the star explained, according to Today.
Faris and Pratt, who share 5-year-old son Jack, announced their separation in August after eight years of marriage. The actress previously confessed on her Anna Faris is Unqualified podcast that the reports about Pratt and Lawrence bothered her.
"In this crazy world where he's off doing movies and I'm in L.A. raising our child, of course I'm going to feel vulnerable, like any normal human would," she said in December. "It made me feel incredibly insecure."