Helgenberger has been married to Rosenberg for 19 years
CSI star Marg Helgenberger has filed for divorce from her husband, fellow actor and Screen Actors Guild (SAG) president Alan Rosenberg.
The 50-year-old, who plays Catherine Willows in the US drama, cited irreconcilable differences when she filed the petition in Los Angeles.
The couple announced their separation last year, saying they had "decided to take some time apart."
They married in 1989 and have a son, 18-year-old Hugh, together.
The pair met when Rosenberg, 58, guest-starred on the soap opera Ryan's Hope, on which Helgenberger appeared for four years.
Court papers show the actress is seeking financial support from her husband while asking the court to deny him any.
"After 19 years of marriage, Marg and Alan have decided to take some time apart," the actress' publicist told People magazine when they first separated.
"They love and respect each other and remain committed to their family."
As president of SAG, Rosenberg has been engaged in a protracted battle over the last year with Hollywood producers, attempting to negotiate new working contracts for its members.