Previously Seen: He was a regular on FX's short-lived war drama "Over There" and had a recurring role as Nicolette Sheridan's troublemaker nephew on season three of "Desperate Housewives."
Expected Breakout Role: Playing J.R. Ewing's chip-off-the-old-block son in TNT's revival of iconic soap "Dallas," premiering June 13.
Why: "Dallas" aims to bridge generations by mixing familiar faces (Larry Hagman, Patrick Duffy, Linda Gray) with fresh blood and Henderson drives much of the drama in the showy role of scheming bad boy John Ross Ewing. His scenes with 80-year-old Hagman crackle with unique father-son tension and he's involved in a juicy love triangle that pits John Ross against his married best friend (Jesse Metcalfe) for the love of another childhood pal (Jordana Brewster).

- Geoff Berkshire