Irish singer/songwriter Niall Horan was one-fifth of One Direction, one of the most commercially successful boy bands of all time. As one of the group's more prolific songwriters, he could also play guitar, which helped him kick off a solo career after the group went on hiatus in 2016. His official solo debut, Flicker, was released in 2017 and topped the charts in the U.S. and his native Ireland.