On September 24, 2000, Westlife, an Irish pop vocal group formed in Sligo in 1998, makes British pop history by becoming the first act to have six consecutive number one singles.

Kian Egan, Mark Feehily and Shane Filan, all schoolmates in Summerhill College in Sligo, participate in a school production of Grease with fellow Sligo men Derrick Lacey, Graham Keighron, and Michael Garrett. They considered it as the start of Westlife. The sextet forms a pop vocal group called Six as One in 1997, which they later rename IOYOU. The group is managed by choreographer Mary McDonagh and two other informal managers. McDonagh first encounters Egan as a six-year-old student at her weekly dance classes, and comes to know Filan and Feehily in their early teens as they star in shows such as Oliver! and Godspell for Sligo Fun Company.

Louis Walsh, the manager of fellow Irish boy band Boyzone, comes to know the group after Filan’s mother Mae contacts him, but the group fails to secure a BMG record deal with Simon Cowell. Cowell tells Walsh, “You are going to have to fire at least three of them. They have great voices, but they are the ugliest band I have ever seen in my life.” Lacey, Keighron, and Garrett are told they will not be part of the new group, and auditions are held in Dublin where Nicky Byrne and Brian McFadden are recruited. McFadden is part of an R&B group called Cartel before this.

The new group, formed on July 3, 1998, is originally named Westside, but as another band is already using that name, the group is renamed Westlife. They manage to secure a major record deal the second time around under BMG with all other record labels competing. They sign a four million pound record deal with RCA Records. Westlife’s first big break comes in 1998 when they open for Boyzone and Backstreet Boys concerts in Dublin.

Westlife has released twelve studio albums. They rise to fame with their debut international self-titled studio album, Westlife (1999). It is followed by Coast to Coast (2000), World of Our Own (2001), Unbreakable – The Greatest Hits Volume 1 (2002), and Turnaround (2003), which continues the group’s success worldwide. The group then releases their cover albums Allow Us to Be Frank (2004) and The Love Album (2006) and the studio albums Face to Face (2005) and Back Home (2007). After a hiatus of studio recording for almost one year in 2008, they release the studio albums Where We Are (2009), and Gravity (2010), and the compilation album Greatest Hits (2011). After eight years, the quartet group releases their eleventh studio album, Spectrum (2019), followed by their twelfth studio album, Wild Dreams (2021).

Westlife is the act with the most Number 1 debuts on the UK Singles Chart, with all 14 of their chart-toppers landing there in their first week. They have the most singles certifications for a pop band on the UK number one singles artists chart since The Beatles. According to the British Phonographic Industry (BPI), Westlife has been certified for 13.1 million albums, 1.3 million video albums, and 10.4 million singles, with a total of more than 24 million combined sales in the United Kingdom (UK). They are also currently ranked 19th with the most number-one albums of all time and sixth-highest band in the list. The group has accumulated 14 number-one singles as a lead artist as well as having eight number-one albums in the United Kingdom, making them Ireland’s and non-British act’s (since Elvis Presley) most prolific chart-toppers. In 2012, the Official Charts Company lists Westlife 34th among the biggest-selling singles artist, 16th amongst the biggest selling groups, and 14th with most top ten hits — all the highest for a boy band and a pop group in British music history. They are also the biggest selling album group of the 2000s, and three of their studio albums are part of the 50 fastest-selling albums of all time in the UK.

Westlife has the most consecutive number one studio albums in a decade in the UK and Ireland for a band, since The Beatles, and for a pop band and act since ABBA. Also in Ireland, they have 11 number one albums with a total of 13 top two albums, 16 number one singles, as well as 34 top fifty singles. They have sold over 55 million records and are holders of the following Guinness World Records: first to achieve seven consecutive number-one singles in the UK; most public appearances in 36 hours by a pop group; most singles to debut at number one on the UK chart; and top-selling album group in the United Kingdom in the 21st century.

Westlife is one of the most successful music groups of all time, among the highest-profile acts in 2000s popular culture in most territories worldwide, and one of the few boy bands to have continued success after their commercial peak. On the best-selling boy bands of all time list, they are currently tenth worldwide along with the biggest-selling boy band from Ireland in history globally. They have received numerous accolades including one World Music Award, two Brit Awards, four MTV Video Music Awards, and four Record of the Year Awards. As a live act, Westlife has sold 5.5 million concert tickets worldwide from their fourteen concert tours so far. They hold the record for the most shows played at The SSE Arena, Belfast and Wembley Arena. This makes them the biggest arena act of all-time in the United Kingdom. They sell out Croke Park in Dublin in a record-breaking five minutes. Their fourteenth, and latest concert tour is called The Wild Dreams Tour.