Photographers spotted the 21-year-old "Let Me Go" songstress and the 24-year-old "Slow Hands" singer spending time in New York City together on Monday.
Pictures show the low-key couple on their way to do some shopping at Saks Fifth Avenue ahead of her performance at Radio City Music Hall.
These photos of the couple come just over four months after the duo first sparked romance rumors. Shortly after relationship speculation surfaced, a source confirmed to E! News that Steinfeld and Horan are an item.
"It's true that Hailee and Niall are dating, but at this point it's still pretty casual," the insider shared with us in March.