An informant told Page Six that 'Wishlist' star Halpern was recently spotted on a series of dates with Styles in New York City.
The insider claimed that the alleged budding romance between the teen popstars is "getting quite serious".
However, Styles's spokesperson has responded to the rumour by denying that he and Halpern even know each other.
"[I've] never heard of her before; Harry is single," Styles's rep said.
Styles was previously linked to UK television presenter Caroline Flack, who recently admitted that she is "very fond" of her former flame.
One Direction were in New York City last week in preparation for their debut on Saturday Night Live.
> Justin Bieber up for One Direction collaboration
> One Direction: 'Saturday Night Live is our kind of show'
Watch One Direction perform 'What Makes You Beautiful' on Saturday Night Live below: