Cowell's three remaining acts Rachel Crow, Melanie Amaro and Drew will take to the stage with the rest of the Top 9 tonight for a Thanksgiving-themed episode of the Fox singing competition.
Writing on his newly-launched Twitter account, judge Cowell teased: "[Melanie Amaro] didn't like the song first of all, now she does!", adding: "It's going to be a big surprise and a big moment."
He told followers that Crow's song choice for the week was "very clever" and hinted that viewers could expect a "big production" in her performance, while Drew "is back on form", adding: "She chose the song, and she's going to nail it!"
Cowell also revealed: "Two of the other contestants have asked me to choose their songs, but I can't!"
The other acts still in the running for the record-breaking $5 million recording contract prize are Josh Krajcik, LeRoy Bell, Lakoda Rayne, Marcus Canty, Chris Rene and Astro.
Last week's X Factor results show saw Stacy Francis sent home after landing in the bottom two alongside Astro following their Rock Week performances.
Speaking to Access Hollywood after the show, Cowell had said the judges couldn't take anything for granted moving forward in the competition.
"We've got to rethink everything," he said, when asked how he felt about the following week's performances. "You have to understand that, you can't take anything for granted. The public can be fickle and they spot things we don't spot so we have to be better."
The Top 9 acts face a double elimination on Wednesday night's results show, which will also feature performances from Kelly Clarkson and Bruno Mars.
X Factor continues tonight (Tuesday) at 8/7c on Fox
> X Factor USA Paula Abdul: 'My heart went out to Astro'
> X Factor USA Astro apologises for results show behaviour
Watch a promo for tonight's Top 9 performances below: