In at least six episodes of the series' fourth season, Knepper will play Samuel, a Jim Jones type -- charismatic but evil, with a twisted sense of humor -- who will veer into the lives of all heroes. The character had been referred to as "Carnival Barker" in the series breakdown released last month.

"Heroes" is slated to return in the fall for a "Lost"-style all-original run in a new time slot at 8 p.m. on Mondays. The sci-fi drama -- which enjoys a strong online following -- will share its time period with another fan favorite, "Chuck," which will take over in midseason.

Production on the UMS-produced "Heroes" is scheduled to begin later this week.