The 22-year-old singer, who has gone on to sell millions after initially being knocked back, said people often criticised him for chubby and ginger looks, reported Sun online.
"Every single label I had gone to at the time had told me this song wasn't a hit. They said this song wouldn't work. And the fact that I was slightly chubby and ginger was not a good 'marketing tool' for them.
"So it did definitely feel like it wasn't going to happen. But being an individual makes you stand out from the crowd," he said.