The super producer revealed that he texted GaGa to see if she would duet with Cher on her new single 'The Greatest Thing' after the pop icon fell in love with the song.
The Moroccan hit-maker told MTV: "[Gaga and I] recorded the song a few years ago, and we were always in the studio enjoying that song. It's weird we never did anything with it.
"So I remember my management and Cher's management were trying to get us together, and I thought, 'Oh my God, I'd love to meet Cher, just to meet her!'
"And so I met her, I played her some songs, and I played her 'The Greatest Thing,' and she loved it. She said, 'This is my song,' I said, 'Yes, it's your song.'"
He continued: "I cut the vocals with Cher first, and I was in Madrid and got a text from GaGa saying, 'I'm thinking about jumping on the song in the remix.'
"I was like, 'No, you should jump on the original! Make it a duet.' She said, 'Oh yes, OK, absolutely,' and then I spoke to Cher, and it became a party."
He added: "Everybody loved it. GaGa on it, Cher, two big icons, [they are] part of music history. So it happened. I'm very happy to be a part of this."
'The Greatest Thing' is expected to premiere in the coming weeks after Cher revealed last month that the track would be first played in September.
Watch the music video for Cher's 1998 hit 'Believe' below: