American Idol winner Clarkson will unveil her new single 'What Doesn't Kill You (Stronger)' on Wednesday's edition of The X Factor, while Mars will sing the Twilight Saga: Breaking Dawn - Part 1 soundtrack's 'It Will Rain'.
The X Factor's theme this week will be 'Giving Thanks' due to the Thanksgiving holiday, which will move the show's broadcasts to Tuesday (November 22) and Wednesday (November 23) night.
The Top 9 will face a double elimination this week as two acts are sent home after facing America's votes.
Fans will be invited to vote as soon as the performance show has ended in one of several ways: Twitter, Verizon Touch Voting on The Xtra Factor App on Verizon Android devices, toll-free calling, text messaging for Verizon Wireless customers, or online at TheXFactorUSA.com.
Fans with valid Facebook accounts can also vote at Facebook.com/TheXFactorUSA.
Last week, judges Simon Cowell, LA Reid, Paula Abdul and Nicole Scherzinger eliminated Stacy Francis from the competition after she fell into the bottom two with Astro.
Astro caused controversy during last week's X Factor results show when he initially appeared reluctant to fight for his place in the competition by rapping for the judges.
The 15-year-old later apologised for his behaviour, saying that he let his passion get the best of him.
> X Factor USA Simon Cowell "frustrated" by Astro
> X Factor USA Stacy Francis: 'I didn't understand Astro's behaviour'
The remaining acts in the running to win the $5 million recording contract prize are: Astro, Josh Krajcik, Melanie Amaro, Marcus Canty, Drew, Rachel Crow, LeRoy Bell, Chris Rene and Lakoda Rayne.
X Factor continues Tuesday at 8/7c on Fox .
> Read Digital Spy's interview with Stacy Francis
> X Factor USA Stacy Francis: 'I'm definitely going to do a record'
Watch Stacy Francis perform 'Amazing Grace' during last week's X Factor results show below: