Bradley Cooper recounted how he first thought of Lady Gaga for the role of Aly in “A Star Is Born” at the film’s L.A. premiere Monday.

Cooper said he first saw Gaga perform live at a cancer benefit at Sean Parker’s house, where she sang “La Vie en Rose.” The song is the same song that Cooper’s “A Star Is Born” character Jackson Maine first sees Aly sing in a drag bar.

“I was floored,” he said. “I’d never heard her sing live before and then I went and met her, I think it was almost the next day. I was so taken with how warm and present and kind and generous she is. And then from that meeting, that was it. There was no movie without her.”