Mark Ronson Reveals How Bradley Cooper And Lady Gaga's Oscars Duet Came To Be

For many, the 2019 Academy Awards will forever be defined by the moment Lady Gaga joined her “A Star Is Born” co-star and director Bradley Cooper onstage to perform the Oscar-winning song  “Shallow.”

The song’s co-writer, Mark Ronson, shared a few behind-the-scenes tidbits about the iconic performance in a Tuesday appearance on “The Ellen DeGeneres Show ,” explaining that Cooper “had a specific vision” for the number beforehand. 

“That probably might be the only time they ever perform that song together, so it made it feel really special,” recalled Ronson, who also collaborated with Gaga on 2016′s “Joanne .”

Though “Shallow” stopped the show cold, Cooper remained refreshingly self-effacing about the performance, Ronson said. 

“Afterwards I went up to him and I was like, ‘You killed it!’ and he was like, ‘Really?!’” he explained. “And I was like, ‘How can you not know?’ But I think that ... he’s not a singer, so it was so brave of him to go up and do that.”

Elsewhere in the interview, Ronson spoke about his time in studio with Gaga. Composing “Shallow,” he said, took only “a couple of days.” 

“She had this idea for the chorus, she sat down at the piano and she just kind of picked a few chords, and then she’s like, ‘I’m off the deep end’ or something and then we all hit the ground running,” he said. “She’s super fast.”

“I love her songs like ‘Bad Romance ’ and… the wild Gaga thing that she does,”  he added. “So I said, ‘We should do something a little weird! I know this is for this film and it’s a ballad, but do your weird Gaga thing!’”

And two days after Hollywood’s biggest night of the year, Ronson has yet to wrap his head around what it means to be an Oscar winner. 

“Making music, Grammys are sort of the epitome of what you shoot for. So this is so much from another universe,” he said. “It’s just another level.”