Blair Underwood ("L.A. Law") Guest Stars "The Passion of the Christine" -- Christine learns that Ritchie believes she and Richard have gotten back together, on the second season premiere of THE NEW ADVENTURES OF OLD CHRISTINE, Monday, Sept. 18 (9:30-10:00 PM, ET/PT), on the CBS Television Network. Executive Producer Andy Ackerman directed the script by Executive Producer Kari Lizer. Blair Underwood ("L.A. Law") guest stars as Mr. Harris, Ritchie's new teacher. Since New Christine broke up with Richard, he's been spending a lot of time at Christine's house, leading Ritchie to believe that his parents are back together. When Christine tells Richard that Ritchie told this to his new teacher, Richard suggests that they give their relationship another try. THE NEW ADVENTURES OF OLD CHRISTINE stars Julia Louis-Dreyfus ("Seinfeld") in a comedy about a divorced working mom who is successfully juggling the daily stresses of motherhood and her business, while maintaining her fantastic relationship with her ex-husband…until his young, new girlfriend enters the picture, instantly complicating her life. Christine Campbell (Louis-Dreyfus) has a busy life -- after all, she's prone to taking Nyquil to get to sleep and leaving voicemail messages to herself in the middle of the night. But, it's a good life: she owns a women's 30-minute workout gym, and her 8-year-old son, Ritchie (Trevor Gagnon), was just accepted into a posh private school where she encounters two snooty stay-at-home class moms, Marly (Tricia O'Kelley) and Lindsay (Alex Kapp Horner), who can't seem to grasp the concept that Christine actually works. Her 20-something slacker brother, Matthew (Hamish Linklater), lives with her but, in a pinch, also serves as Ritchie's babysitter and has an uncanny knack of getting him to do anything Christine can't. Also, she gets along with her charming ex-husband, Richard (Clark Gregg), even better than when they were married. But easy street is suddenly filled with a major pothole when Christine discovers that Richard has a new girlfriend: a young, nice, impossible-to-hate woman also named Christine…the "new" Christine (Emily Rutherfurd), and that doesn't sit very well with "Old Christine." Now, as Christine realizes that Richard is moving on with his life, it dawns on her that maybe it's time for her to take that same leap. THE NEW ADVENTURES OF OLD CHRISTINE is produced by Warner Bros. Television Productions, Inc. Kari Lizer and Andy Ackerman are the executive producers. SERIES REGULARS Christine Julia Louis-Dreyfus Richard Clark Gregg Matthew Hamish Linklater Ritchie Trevor Gagnon Marly Tricia O'Kelley Lindsay Alex Kapp Horner GUEST CAST Mr. Harris Blair Underwood Ashley Lily Goff Kelsey Marissa Blanchard RATING: To Be Announced COMEDY On the web: http://www.cbs.com/primetime/old_christine/ Photo is available on www.cbspressexpress.com