The nervous actress was trying to remember her acceptance speech after landing a Best Actress honor for "Silver Linings Playbook" and tripped up the stairs heading to the stage at the Dolby Theater.
The fall left the star red-faced and flustered but her embarrassment turned to anger when she heard Cooper had suggested she faked the slip-up to grab attention.
"I didn't want to write down a speech, I had everything in my head," Lawrence told Heather McMahan's "Absolutely Not" podcast. "Then I fell, and it just erased everything from my mind. My full brain went blank. I can look back at it now I'm a little older fondly, but for a very long time the fall thing was very sensitive... It was so devastating because it was this horrific humiliation to me."
And when Cooper declared she "obviously faked the fall" days later, Jennifer was livid - so much so that she challenged the newsman years later at a holiday party, at which they were both guests.
"I let him know," she recalled. "My friend told me that a vein was bulging out of my eyes, but he apologized. I think we're good friends now. On my end, we're all good. What I led with was, 'Have you ever tried to walk up stairs in a ball gown? So then how do you know?' He apologized immediately and was like, 'I didn't know', and gave this wonderful apology. I was all fired up... He probably told everyone I was a psycho."