One Direction singer Niall Horan has undergone quite the transformation for the boyband's new single, Best Song Ever.

The single, now available for pre-order, is released on July 22.

It is also the title track from the group's upcoming third album.

One Direction's movie, This Is Us, is released in cinemas on August 29.

Niall Horan

Niall Horan

Niall Horan