He's the second from One Direction to chase a solo career, after early-exiter Zayn Malik released 'Pillowtalk' in January.
Unlike Malik, Horan's track 'This Town' isn't a big departure from his old music. It's a cruisy ballad about a break-up, led with his acoustic guitar.
Horan says he's been blown away by all the positive feedback.
His former bandmates have also publicly supported him, with Louis Tomlinson saying he's "super proud" and Harry Styles praising it as a "lovely tune".