In a video shared via Instagram Live, the World of Dance judge told fans she whispered a few words to Cooper before he joined his A Star Is Born co-star, Lady Gaga, on stage to sing the movie's Oscar-winning song, "Shallow."
"He seemed a little nervous," Lopez revealed. "I just whispered, I said, 'The song is so beautiful. When they hear the first few notes, they're going to start applauding. So don't worry. Just deliver the song.'"
"He was like, 'I got it, I got it, OK,'" she added.
In case you missed it, Gaga and Cooper's performance was one of the most memorable of the night, thanks to their undeniable chemistry. Fans and celebrities alike couldn't seem to get enough of it, with some even wondering if a real romance was brewing between the two.
A source told ET on Tuesday that although Gaga and Cooper had an incredibly strong connection right from the start, they have kept their relationship strictly professional while working together on A Star is Born.
"They are both very hard-working, driven people and during the making of the film, had a very professional work relationship," the source said. "From the moment they began collaborating with each other, people on the set saw how connected they were, which is why everyone wants their relationship to be real. There is endless chemistry between them."
"When they're together, they complete each other's sentences," the source continued. "They are creatively so in tune with one another and seem to have a total intuition with one another."