It made front page headlines last March when the 1D heartthrob was reported to be dating Dublin model Zoe Whelan after she accompanied him to the wedding of his brother Greg.
More excitement ensued when Zoe turned up at several One Direction gigs.
Soon after the Coolock woman was signed up by model boss Andrea Roche and in demand for photocalls, with the 18-year being likened to starlet Selena Gomez, who had a long-term relationship with pop singer Justin Bieber.
Only one problem with all this.
Niall Horan's dad Bobby is adamant his son doesn't have a girlfriend.
"If Niall had a girlfriend, I'd certainly know about it, and he's never said anything about a girlfriend. Niall is definitely single, and I hope he remains that way," Bobby told The Diary.
Bobby called brunette Zoe "a lovely girl" when he met her at his other son Gregg's nuptials in Lough Rynn Castle in Co Leitrim.
It's just that he believes his multi-millionaire son is "too busy for a girlfriend".
And dating one could be nigh on impossible, said his dad, with Niall travelling the globe for the next year in One Direction's Where We Are stadium tour.
"Niall's chock-a-block but more importantly, I think he's much too young for a serious relationship.
"I'd advise him against that," added the Westmeath man.
Zoe could be getting off lightly as the brunette suffered a torrent of abuse from jealous 1D fans when it was reported she was stepping out with Niall.
The disgruntled fans even went so far as to set up fake Facebook page and Twitter accounts to impersonate her.
The pages has since been removed but the critical comments aimed at Zoe might put off any future starlets considering hooking up with the One Direction star.
Not that Niall could get lonely, dad Bobby reveals how Niall still finds time to sneak back home to Mullingar.
"Out of the blue he can ring up and tell me he's coming home."When, I'll say?" In about twenty minutes, I'm on the road to Mullingar."