Mark Ronson: Uptown Funk led to hair loss, sickness and collapse
Uptown Funk is the biggest hit of the decade - but Mark Ronson revealed that producing it made him so ill he ended up slumped and sick in a toilet.
The song has more than 1.3 billion hits on YouTube, went to number one around the world, and sold millions globally.
But the British producer, 40, told The Mail On Sunday's Event Magazine that he became so anxious trying to finish the hit he lost an inch off his hairline.
He said: "I had everything going on - hair loss, anxiety attacks, vomiting and finally collapsing in a restaurant."
The hit was conceived in "literally seconds of inspiration" in Bruno Mars's studio in collaboration with musician Philip Lawrence and producer and songwriter Jeff Bhasker.
But Ronson said that after six months and 54 different versions he was still struggling to finish it.
He told the magazine: "Jeff suggested going to a restaurant and then he asked me if I was OK because I looked incredibly white in the face.
"I went to the toilets and just started vomiting, then I collapsed and had to be carried out of the restaurant. And then a couple of weeks later it [the guitar part] just came."
Ronson became seriously hot property in the music business after collaborating with Amy Winehouse on her album Back To Black.
But he spent several years in the musical wilderness before bursting back on to the scene with the catchy collaboration with Bruno Mars.
It is nearly five years since Winehouse died from alcohol poisoning, and Ronson said he misses her deeply.