Harry, 21, met 37-year-old Nicole Scherzinger when he was just 16-years-old and auditioning for The X Factor as a solo artist.
Former Pussycat Doll Nicole had a say in the creation of 1D, putting Harry in a band with Liam Payne, Niall Horan, Louis Tomlinson and Zayn Malik.
Three years later, when Harry was 19, she allegedly enjoyed a brief romance with the heartthrob – while she was on a break from Formula One racing driver Lewis Hamilton.
A source told The Sun: “They had a dalliance at the end of the X Factor in 2013 and met up again early last year.
“Harry was obviously very taken by Nicole who is stunning and he had always looked up to her.”
The insider added: “She was a guest judge on X Factor at the time One Direction were formed and has always claimed credit for putting the band together, even though Simon Cowell says it was his idea.
“But they hooked up over there years later when Harry had matured and was a member of the world’s biggest band.”
One of Harry’s most famous relationships was with X Factor presenter Caroline Flack, when he was 17 and she was 31.
Of their brief romance, Caroline said: “I’m not going to ever apologise for it because there was nothing at the time that was serious or bad and nobody was getting hurt.”