Blue are a British boy band consisting of members Simon Webbe, Duncan James, Antony Costa, and Lee Ryan. The group formed in 2000 and released three studio albums before announcing a hiatus in late 2004. In January 2011, the group reformed and represented the United Kingdom at the 2011 Eurovision Song Contest in Düsseldorf with the song "I Can", coming in 11th place with 100 points. In 2013, it was confirmed that the group would be joining The Big Reunion, in which six groups from the past reform for a one-off gig. On 27 March 2013, the group announced they would embark on their first headlining tour later on in the year, their first tour in nearly ten years.

A boy band is loosely defined as a vocal group consisting of young male singers, usually in their teenage years or in their twenties at the time of formation. Generally, boy bands perform love songs marketed towards girls and young women. Many boy bands dance as well as sing, usually giving highly choreographed performances. South Korean boy bands usually also have designated rappers.