Mark Ronson found making 'Uptown Funk' so stressful it caused him to faint.
The 39-year-old producer made the chart-topping tune in collaboration with Bruno Mars, 29, but says getting the song to his liking caused him to feel ill.
He revealed: "We did 45 takes of it and I just couldn't get it, it sounded like horrible bull***t, so we went to lunch, walked down to a restaurant. Everyone was saying: 'Dude, what's wrong with you? You've gone totally white.'
"Because I was going on pretending everything was just fine; you don't want to admit that you're just not there, you're not where you want to be. And I went to the toilet and just ... fainted. I threw up, and fainted. They had to come and carry me out of the toilet."
Mark - who is best known for his collaborations with Amy Winehouse - admits his career had "gone cold" prior to the success of 'Uptown Funk'.
He told The Observer newspaper: "You know you're cold, industry-wise, because you see all the gigs going to your friends. OK, I understand, so they think that I'm just the guy that did [Amy's album] 'Back to Black' six years ago, and that's pretty much all.
"I don't know, it's probably all my weird hangups and neuroses, a lot of it."
Tagged in Mark Ronson Amy Winehouse Bruno Mars