Now it's emerged the girls actually auditioned for the talent show as solo singers before being sent to a group boot camp and put together in the band, which then re-auditioned for judges.
An X Factor rep told The Sun: "Four of Diamonds did all apply for the show as soloists but didn't make it past the first stage. They were then invited to take part in a workshop to form a group, the group then had to apply again to enter the show."
Of course, it's not the first time the show has suggested solo singers group together to form a band: it famously happened with both One Direction and Little Mix in previous years. Those bands, however, were seen forming on TV as part of the show, whereas Four of Diamonds' formation was done off camera.
Four of Diamonds - Sophia, Caroline, Yasmin and Lauren - were initially sent home by groups mentor Louis Walsh at his Judges' Houses in Ibiza, which was a shock to many viewers who felt at least one girl band should have made the live shows.
The girls got a second chance, however, when twins Brooks Way withdrew from the competition this week amid allegations about Josh's personal life.
In a statement, Louis said: "I was really impressed with the girls at Judges' Houses but only had three spots to fill for the Live Shows.
"At the time a lot of viewers were disappointed that I didn't put the girls through, now that a place has opened up in my category, I've listened to the fans and am delighted to be bringing the girls back.
"They're a great girl group and I'm hoping will take me all the way to the final."
The X Factor, Saturday and Sunday at 8pm on ITV1.