William Petersen

CSI fans take heart: A feature-length movie is in the cards, and it's definitely going to involve Gil Grissom, according to William Petersen.

"Yes, there will be a movie," Petersen told Britain's Radio Times. Although he is sure fans might be "a little trepidatious," Petersen promises the move to the big screen will not be done haphazardly.

"Usually people leave it till a series has finished —they did that with The X-Files and Sex and the City," Petersen said. "But it's about finding the right story, there has got to be a real reason to do it."

One of those real reasons? Grissom won't be around forever. "You don't just do it because you want to make money — you do it because there's a story that can't be told on TV and needs to be told from CSI's perspective and the audience wants it," Petersen said. "And we can't wait for CSI to end or Grissom will be about 90."

Petersen bowed out of the hit CBS drama after eight years earlier this season, handing over the reins to Laurence Fishburne's Raymond Langston. He had previously said his character's open-ended departure preserved the chance of a film.