When CSI returns with new episodes in 2011, viewers will be treated to a couple major guest stars.

First, producers Carol Mendelsohn and Don McGill tell Entertainment Weekly that  will show up next month as a woman with “a dark secret,” someone for whom Greg puts his life on the line.

Also, “look for something about Greg’s first kiss and maybe something more,” the producers wrote in an email.

Justin Bieber will also reprise his role as troubled teen Jason McCann in February.

Look for Nick, who killed Jason’s brother on the September premiere, to try and save Jason. He will be “putting himself and the team in jeopardy," Mendelsohn and McGill said.

What exactly does that mean? We're excited to tune in and find out.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.