Mark Ronson feared he had suffered at stroke aged 20 because of his drug use.

The 50-year-old songwriter and record producer admits that he fell into substance abuse before finding fame as he recalled a terrifying experience he had after mixing drugs while out partying in New York during the 1990s.

Writing in his new memoir Night People, Mark recalled: "One night, when I was out late and already flying on E, I took a bump of coke. Within minutes, my chest tightened and my left arm went numb. Could I having a stroke? At 20?"

Ronson explained how his drug habit spiralled even further after producing his first record in 2001 and confessed that he was "lucky" to survive.

The star - who has produced songs for the likes of Amy Winehouse, Adele and Bruno Mars - told The Sun newspaper's Bizarre column: "My drug use and that side of things got even worse really, as I got older.

"Outside of the time of the book, I would say it was really in my late thirties, early forties and around (albums) Version and into Record Collection that I was really going the hardest.

"I'm not smart enough to know how addiction works. I don't know if you can ever really fully navigate that path and keep yourself from falling over the edge, where I was just lucky.

"But there was just this time at which I knew that there's nothing in this for me any more.

"I would lie to myself, you know, 'I just work really hard. So this is how I blow off steam.'

"I just realised, no, this is whatever you want to call it, a weakness, or this is like a way to skirt reality.

"I clearly liked it more than a lot of people. And then luckily less than some other people."

Mark is now drug-free and happily married to actress Grace Gummer - and explained that his mother-in-law Meryl Streep has plenty of musical talent.

He said of the legendary movie star: "We actually didn't have a DJ at the wedding, but she's an insanely good singer.

"Well, I guess everybody knows that from Mamma Mia! and she knows music so well.

"It's both instinctual and, you know, brainy level. So I love playing music that I'm working on. I really respect and value her opinion when it comes to music."