Both singers were controversially cut at the Judges' Houses stage of the competition in 2011 and have returned for a second crack.
Returning acts have a mixed record on The X Factor. Alexandra Burke's second bash at the show ended in the ultimate glory - a duet with Beyoncé and the series crown. Others such as Rikki Loney reached the Live Shows, but quickly crashed out.
Meanwhile, Marlon McKenzie, John Wilding and Annastasia Baker have become gluttons for punishment, losing out at Judges' Houses on more than one occasion.
Have the judges got it wrong in the past? Is there a former contestant you'd love to see return? Reality Bites looks back at some of the Ones That Got Away on The X Factor:
The most famous of all X Factor Judges; Houses rejects, Gamu was the star of the show at the auditions, before being suddenly dumped out by Cheryl Cole to shock and outrage from the nation. Not only did Chezza take walking irritant Katie Waissel over her, she also didn't even bother bringing Gamu back as a Wild Card, opting for Treyc Cohen instead. Treyc who? Exactly!
A hunky American with husky rock vocals. What was not to love about Ethan? Once again it was Cheryl Cole who made the call, picking Lloyd Daniels and Rikki Loney over poor Ethan. Judging by Dannii Minogue's ogling, he'd have been a definite yes in her category.
They went on to achieve novelty pop success several years after they appeared on the show, but that still doesn't stop us wondering how this rough-around-the-edges pop combo would have fared if they'd been given a crack on the Live Shows.
Not axed once but twice, Annastasia was really put through the emotional ringer on The X Factor. It's unlikely she'll return for a third time after doing tabloid interviews hitting out at the show following her second axing in 2010.
Boot Camp in 2005 and 2008. Judges' Houses in 2010. And then dumped from The Risk before they made the Live Shows in 2011. To say Marlon has been unlucky on The X Factor is a very small understatement.
He even went to the bother of buying a nice hat and getting his teeth done for his second crack at The X Factor. It still wasn't enough to make the Live Shows. Sad face.
Purely for his name, we want him back.
One Direction didn't do badly, but surely these guys deserved a spot on the Live Shows ahead of Diva Fever, FYD or Belle Amie?
Which acts do you think should have made the Live Shows? Who would you like to see given a second chance? Let us know below.