Comedy writer Kevin Smith has signed a deal to write and direct an episode of the upcoming prequel series Heroes: Origins.

Smith - who has also penned comics for Green Arrow and Daredevil - will work on a one-off episode for American network Nbc.

He jokes, "I just don't want to be the guy who ruins Heroes."

Meanwhile, Adrian Pasdar - who plays Nathan Petrelli - reveals each of the heroes will be given a big storyline in the prequel series.

He says. "Last year we were looking to talk to anybody who wanted to talk to us."

"This year the degree of secrecy is a lot higher in what we can say. No matter who your favourite character is, the things that are going to happen in this season will be exciting to the point of being numbing for fans."

"This season is not about defining them by their own behaviour? there's a lot more at stake."