The 18-year-old One Direction singer is reportedly dating 24-year old Sarah-Louise Colivet from Kildare after meeting her in the US.
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Styles is said to have met up with the New York-based photographer during the band's recent US tour, reports the Irish Sun.
Colivet's mother Jacinta revealed that her daughter had informed her about the alleged relationship.
"It's true, she has struck up a friendship with him," she said. "She rang and said he was lovely, great fun and a really nice guy.
"She met him in New York - she is a cool customer though, so she wasn't going to tell her mum too much. I don't think she realised that girls go that crazy for him until now.
"He has gone on to Australia now, but they will definitely stay in touch."
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Friends close to Colivet have said that the pair have got "very close, very quickly" since they met after a One Direction gig.
One friend said: "Sarah-Louise and Harry met after one of 1D's gigs and just hit it off instantly. She's a stunning girl, really fun and outgoing, and it's no surprise she caught Harry's eye.
"She's understandably keeping things under wraps - he's explained to her he has to be seen as single under strict orders from bosses - but she can't always hide her delight.
"She even posted a saucy message (on Facebook) about Harry being with her the 'morning after' but quickly deleted it."
Styles recently denied that he had been dating 19-year-old singer Lily Halpern.
The singer was previously romantically linked to television presenter Caroline Flack, who recently admitted that she remains "very fond" of the star.
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