One Direction (commonly initialised as 1D) are an English-Irish pop boy band based in London, comprising of Niall Horan, Liam Payne, Harry Styles, Louis Tomlinson and former member Zayn Malik. Zayn left the band on March 2015. They signed with Simon Cowell's record label Syco Entertainment after forming and finishing third in the seventh series of the British televised singing competition The X Factor in 2010.
One Direction and Little Mix are labelmates. (Syco)
One Direction and Little Mix performed Wishing On A Star together with the other finalist. That's where Perrie and Zayn met.
The band supported Little Mix. Jesy Nelson said, "[One Direction] basically told us to go over [to the U.S.] and be ourselves. There's nothing more you can do – you just gotta try your best and hope for the best."
Little Mix were support band for 1D on Apple Music Festival 2015.