A fan site for Alexz Johnson has confirmed the Canadian pop singer and actress will play Saturn Girl in an upcoming episode of Smallville, written by Geoff Johns.
The episode, titled 'Legion,' also features Cosmic Boy and Lightning Lad. The three come from a future where Clark is the greatest hero.
Oh, and if you aren't already reading it, check out the Legion of 3 Worlds mini that is one of the Final Crisis tie-ins. Both Legion stories are scripted by Johns, who is a solid writer who puts in a good story.