Which Irish band had their first two singles "Swear It Again" and "If I Let You Go" reach Number One in the UK?

Westlife was an Irish pop vocal group, which formed in 1998 in Dublin and disbanded in 2012. Originally signed by Simon Cowell in UK, Clive Davis in the United States and managed by Louis Walsh, the group's line-up consisted of Nicky Byrne, Kian Egan, Mark Feehily, Shane Filan and Brian McFadden, who was a member until his departure in 2004.

Westlife's first big break came in 1998 when they opened for Boyzone and Backstreet Boys' concerts in Dublin. Later, they won a special Smash Hits Roadshow award at that year's Smash Hits Poll Winners Party. In April 1999, the group released their first single, "Swear It Again" which immediately topped the charts in Ireland and in the UK for two weeks. It became the biggest-selling single in a week one by a debut artist. Their second single, "If I Let You Go" was released in August 1999, which established them as the first boy band to hit the No. 1 with its first two singles.

Westlife sold over 40 million studio albums and 55 million records overall worldwide. Based on BPI (British Phonographic Industry) certifications, the group have sold 11.1 million albums and 6.8 million singles in the UK. The group accumulated 14 number one singles in the United Kingdom and 26 UK top ten singles over their 14-year career.