Meet Smallville's Saturn Girl

via IO9:

Telepathic cutie Saturn Girl is finally making her appearance on Smallville, thanks to Geoff Johns' episode that not only ushers in our perky hero from the future, but a few other members of the Legion of Super Heroes. Playing the girl who's inside everybody's minds is pop star Alexz Johnson.

That brings us to a fan page of Alexz's:

Yes, to answer questions that people keep asking me about: the rumours that Alexz is guest-starring in the long-awaited “Legion” episode of Smallville are true… she is filming this episode as she awaits the final mix of what may be the final song for her album...