Ages: JJ, 23; Josh, 19; Jaymi, 21; George, 18
Mentor: Louis Walsh
Bio: Originally called Triple J, the boyband were ejected from The X Factor before boot camp but were called back when Rough Copy left the competition.
With new member George added to the line-up and the band's name changed, the boys won their place in the finals with their version of Carly Rae Jepsen's Call Me Maybe.
Explaining his reasons for putting the group through to the live shows, judge Louis Walsh said: "The boys have a great young image, girls are going to love them, they have it all – great energy, looks and the vocals to match."
What we said: "Union J are a One Direction with vocals who are dark horses for the whole thing, you mark my words. I've been wrong before." (week seven, judges' houses)
RT predicts: Not fancied by the bookies, but their similarities to One Direction – young, good looks, only finally assembled at judges' houses – make them contenders, and their vocals are solid. 1D are so popular, any decent boy band has to have a chance now. 2nd