Amaro will be returning to The X Factor a year after winning the show's first season to promote her upcoming debut studio album Truly.
Ke$ha is slated to perform her latest hit 'C'Mon', which features on her sophomore LP Warrior.
X Factor hosts Khloe Kardashian and Mario Lopez will also announce which act has been cut following next Wednesday's 'Your Song Choice' theme night.
Last night's results show featured Alicia Keys performing 'Girl on Fire' as well as an appearance by season one finalist Josh Krajcik.
The X Factor USA airs on Wednesdays and Thursdays at 8/7c on Fox in the US, and on Thursdays and Fridays at 8pm on ITV2 in the UK.
Listen to Ke$ha's latest hit 'C'Mon' below:
Photo Gallery - 'X Factor' Live Show for November 28: