They triumphed in the contest's final and topped the UK singles charts with their version of Damien Rice's Cannonball.
They have since released four albums, with this year's Glory Days going straight in at number one.
On November 26 this year they joined Craig David, Professor Green, Olly Murs, Louise Johnson, Busted, Clean Bandit, Sigala, Dua Lipa and Calum Scott at the Genting Arena for Free Radio Live. Little Mix were last part of the annual event's line-up in 2013.
Salute: Little Mix in 2013
Debut album, DNA, released in 2012, was a hit in Britain and America, as was the follow-up, 2013's Salute.
In many ways, however, it was their third album, 2015's Get Weird, that was the real turning point for Little Mix. Released in the hugely competitive month of November it crashed into the UK chart at number two, spent the rest of that year in the top ten and by August 2016 had become the biggest-selling album of their career.
Get Weird: Little Mix in 2015
With over seven million records sold and worldwide arena tours under their belts there's no stopping them – Glory Days was released on November 18, 2016, just in time for the Christmas market.
Little Mix's Glory Days Tour, 2017:
Oct 9 & 10: Aberdeen AECC; Oct 11: Newcastle Metro Radio Arena;
Oct 13: Birmingham Genting Arena;
Oct 14: Leeds First Direct Arena;
Oct 16: Liverpool Echo Arena;
Oct 17: Sheffield Arena;
Oct 19: Glasgow The SSE Hydro;
Oct 20: Manchester Arena;
Oct 26: London The O2;
Oct 27 & 28: Sheffield Arena;
Oct 30 & 31: Cardiff Motorpoint Arena;
Nov 1: Liverpool Echo Arena;
Nov 3 & 4: Newcastle Metro Radio Arena;
Nov 6: Dublin 3Arena;
Nov 7: Belfast The SSE Arena;
Nov 10 & 11: Glasgow The SSE Hydro;
Nov 13: Leeds First Direct Arena;
Nov 14 & 15: Nottingham Motorpoint Arena;
Nov 17 & 18: Birmingham Genting Arena;
Nov 20: Liverpool Echo Arena;
Nov 21 & 22: Manchester Arena;
Nov 25 & 26: London The O2.