Dominic Monaghan was confirmed as a series regular on FlashForward earlier this month.
But, at Comic-Con last week, more details were revealed about the role the former Lost star would play on the new series.
Monaghan will portray Simon, "a game-changer character who f--ks up a lot of things," as described by producer/writer David Goyer.
As for why he signed on for FlashForward, the actor said:
"I want to play someone who's the opposite of [Lost's] Charlie. Simon is a man - this guy's not scared, he's capable, he's unflappable, he's smart, he's scary, he's everything that Charlie wasn't... it's important to me to continue to show an audience that I can play more."
Monaghan added that Simon is a "little hard to predict. He's a snappy dresser, capable and cocky."
FlashForward, one of the fall's most promising new shows, debuts on September 24.