British singer Rebecca Ferguson is convinced her career started to go downhill after her relationship with One Direction star Zayn Malik became public knowledge.

Ferguson shot to fame in 2010 when she was named runner-up on Britain's The X Factor, ahead of boyband One Direction in third place, and she was later revealed to have struck up a romance with group member Malik, who, at 18, was five years her junior.

The mother-of-two eventually split from Malik, who is now engaged to pop singer Perrie Edwards, and she is convinced many fans deserted her because of her relationship with the heartthrob.

She tells Britain's The Independent newspaper, "That (dating Malik) was my first mistake. I was 23, he was 18. Of course, if it was a 23-year-old guy dating an 18-year-old girl, no one would have batted an eyelid, but this way around was a big deal, apparently. I didn't realise that. I was just a hippy, free-loving person, but that's not a good thing to be in this industry. You can't just follow your heart."