Tamera, 16, impressed the judges enough to land a place in the live finals and 35-year-old Katie believes she can go all the way.
Writing in her column with The Sun, the former glamour model said: "Tamera Foster is my tip - fabulous voice, stunning looks and she is only 16."
She added: "So what if she's a bit of a rascal. Cut her some slack - she's only a kid."
The X Factor live shows kick off tomorrow night (12 October) and Tamera is in Nicole Scherzinger's Girls category, alongside Hannah Barrett and Abi Alton.
On Wednesday, Tamera looked every inch the superstar as she arrived for an interview at Radio 1 studios in central London.
Tamera already has a big following on Twitter, with more than 32,000 fans. She previously told them: "I find it so amazing that I have fans from all over the world, I see and love all of you thank you so much."
Check out the final 12 contestants in our gallery below:
Copyright: ITV Tom Dymond/Thames TV