The One Direction heartthrob - who is renowned for his womanising ways - hit it off with model Millie Brady at a BRIT Awards after-show party last month and the pair had agreed to go on a date at the weekend after Harry and his bandmates performed their show in Cardiff, Wales.
But Harry cancelled at the last minute as he decided he doesn't have time for a girlfriend at the moment.
A source told The Sun newspaper: "It was nothing personal - he just wants to keep things casual with Millie at the moment. He had messaged saying he would meet her, then he didn't show. Millie did feel a bit let down.
"I know she was very much looking forward to meeting him again. But it's not going to work out between them any time soon."
Millie had travelled from her home in Virginia Water, Surrey, with a group of friends to watch One Direction at Cardiff's Motorpoint Arena.
She then waited at the city's exclusive Kuku club after the gig for Harry, but the singer never showed up.
Harry, 19, most recently dated Taylor Swift, but the pair split in January, and in 2011 he had a fling with 33-year-old TV presenter Caroline Flack.
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Expecting the unexpected is par for the course for the members of ITSA Theatre Company, which is staging its annual Improvised Panto at the Half Moon Theatre in Cork from Dec 6-21. Now in its third year, this fun event is, to some extent, guided by the over-16s audience.