The star, who has spent the past decade playing forensics expert Catherine Willows in the drama series, is shooting her final scenes for the show, and will walk away early next year (12) - and she admits she is getting emotional as she prepares to leave.
In an interview with news show Entertainment Tonight, which aired on Wednesday (07Dec11), she said, "I think, 'How can I leave this? How can I leave such a wonderful (job)...' I don't even think of it as a job. It's people that I've been with for 12 years. It's been a fifth of my life."
Wiping away tears, she added, "It's been quite a ride... I'm sorry. I didn't mean to get so emotional... I've been really lucky."
Helgenberger has appeared in over 260 episodes of CSI and was among the original cast members when the series debuted in 2000.
The actress will be replaced on the show by Elisabeth Shue.