Elisabeth Harnois, who co-starred on CBS’ Miami Trauma, will be joining the cast of another CBS/Jerry Bruckheimer drama as a regular, the mothership CSI series. She was originally signed to guest star in the May 5 episode as the estranged daughter of Conrad Ecklie (Marc Vann), who works for the Los Angeles Police Department and helps the Las Vegas crew hunt down serial killer Nate Haskell (Bill Irwin). The guest stint grew into a bigger role on the show. She was expected to return for more episodes and has now been upgraded to a full-blown regular status on the show. Veteran CSI, now in its 11th season, has not been officially renewed for next season, but that is considered a foregone conclusion. Harnois, whose series credits also include Point Pleasant, Dirt and One Tree Hill, recently starred in the Disney movie Mars Needs Moms and will next be seen in Riddle opposite Val Kilmer. She’s with WME and Schachter Entertainment.