Which Westlife song was the Irish boy band’s first UK number-one single?

“Swear It Again” was Westlife’s first UK number-one single.

Released in April 1999, the song was the Irish boy band’s debut single and the first release from their self-titled debut album. It was written by Steve Mac and Wayne Hector, with production by Mac and collaborators who helped shape Westlife’s polished vocal-pop sound.

“Swear It Again” entered the UK Singles Chart at number one, immediately establishing Westlife as a major chart act. The group became especially known for romantic ballads, close vocal harmonies, and a remarkable run of UK number-one singles.

Listeners sometimes name “Flying Without Wings” because it is one of Westlife’s best-known songs. That single was released later, in 1999, while “Swear It Again” was the group’s first chart-topping release.