The two artists will appear on the Thursday (December 8) results show, when another contestant will be sent home from the competition.
X Factor said goodbye to Brian 'Astro' Bradley and Drew on this week's results show following their Michael Jackson performances on Wednesday night, leaving just Chris Rene, Marcus Canty, Melanie Amaro, Rachel Crow and Josh Krajcik in the running for the $5 million prize.
Each of those acts will perform two songs on next week's performance show, which airs Wednesday, December 7 from 8/7c on Fox.
Previous guest performers this season have included Rihanna, Bruno Mars, Kelly Clarkson and British rapper Tinie Tempah, who performed 'Pass Out' on this week's results show.
> X Factor poll results: Josh Krajcik rules Michael Jackson Week
Watch Tinie Tempah's X Factor performance below: