Marg Helgenberger says goodbye to "CSI"

"Why not?" she laughed. "Well, I've certainly played my share of women that didn't have the glam factor or whatever."

One of those women was a young mother dying of cancer opposite Julia Roberts in "Erin Brockovich." At the time, her own mother had just completed treatment for breast cancer.

Since then she has become a frequent cast member, singing duets, in an L.A. breast cancer fundraiser called "What a Pair."

Helgenberger was married to actor Alan Rosenberg for 19 years. They divorced in 2010. They have one son, Hugh, who was born in 1990.

"You're too young to have a 21-year-old son," Blackstone said.

"Oh, no, I'm not, but thank you for saying that!" she replied.

At 53, she knows some in Hollywood might consider her old, but she is undeterred by the thought of starting anew. Her last "CSI" episode airs later in January. It was shot last month and she admits saying goodbye was tough, both for her and for her character, Catherine Willows. She got emotional just recalling it.

Usually on "CSI" Helgenberger was composed, cool and seemed to have all the answers. But ask her now what she's going to do next, and for the first time in 12 years . . . she doesn't have a clue.