Rumor: Jackie Earle Haley as Sinestro in Green Lantern?

He's played Rorschach and Freddy Krueger, now he'll play Sinestro in Green Lantern?! Unless you're a Green Lantern fan, you probably don't know who Sinestro is, but we'll explain all that. AICN is reporting a rumor (take this with a grain of salt) that actor Jackie Earle Haley has been cast as Sinestro, the lead villain, in the Green Lantern movie being directed by Martin Campbell and co-starring Ryan Reynolds as Hal Jordan. Not only that, but they say that Superman has a cameo in it as well (the character, not Brandon Routh). Though I'm not sure if I can believe all this yet. If it's true, then this is some seriously great casting.

AICN says their source is "someone working on the film," meaning it's legit, but I'm going to wait to hear it from Warner Brothers or Haley himself before calling it confirmed casting. So who is Sinestro? Sinestro ...