Charlie Puth feared he was working himself to death in his quest to become a popstar.
Although he'd had a few minor chart hits and featured on Wiz Khalifa's U.S. number one single See You Again, until the release of Attention last year (17) Charlie was still searching for a signature hit - and was touring extensively and working on new music.
The 26-year-old, who has previously admitted to taking steroid injections to avoid cancelling gigs, said that he was labouring so hard he made himself so ill he worried he'd die.
"I was working way too hard and being mismanaged before my sister came on board and fixed everything," he told Britain's Daily Star newspaper. "I thought I was going to die. The doctor told me my immune system had depleted by 75 per cent. I hadn't been healthy for a year and my body couldn't recover. And it was just because I was trying to make as much music as I could on the road and try and impress everybody."
Charlie revealed that the reason he pushes himself so hard is his concern that all the trappings of fame will quickly disappear the moment his popularity wanes.
"I thought it was going to be easy," he explained. "I thought it was nice hotels and getting into any restaurant you want to, and I do get that, but I have to work really hard to ensure I continue getting that."
The moment he wrote Attention, which reached the top five of the U.S. Billboard Hot 100 chart, Charlie knew he had a hit, and it made him relax a little and free time up from his punishing schedule.
He is still keeping a fairly impressive workload, however, as he has spent large parts of the last two years back on the road, and released his second album, Voicenotes, earlier this year (18).