Jordin Sparks and Blake Lewis by Frank Micelotta/Fox Jordin Sparks and Blake Lewis by Frank Micelotta/Fox
American Idol finalist

Blake Lewis tells that come Tuesday night, he and

Jordin Sparks will sing one song they have performed previously; a new tune of their own choosing; and, to complete their set, the winning ditty from this season's songwriting competition-within-a-competition - "but that's all I can reveal." In a separate conference call, Jordin told reporters that Simon Cowell's comments - namely, his recent riffs that her song picks sometimes skew too old for someone all of 17 - "always stay with you. But at the same time, I can't really base what I'm going to do off of that, even though I can and sometimes do." But in this particular, kinda-important instance, will she embrace a "youth" movement? "Next week, I have a more youthful song in my repertoire that I'm going to pull out," Jordin previewed. "So I'm really excited." POLL: Might beat-boxer Blake best Jordin to win? Vote here.