A cast shake-up for ''Ally McBeal''

EXITS ”ER” isn’t the only hour-long show to experience cast migration: ”Ally McBeal”’s Courtney Thorne-Smith will leave the quirky David E. Kelley show with hopes of starring in her own sitcom. Thorne-Smith, who plays Georgia, will finish this season and head out at the same time as her on-screen husband Gil Bellows, who plays Ally’s first love, Billy. Kelley said in a statement that he’ll introduce new characters this year, and have Billy and Georgia pop up at the beginning of the fall season for their farewell episodes.

PROPS His music lives: Don McLean approves of Madonna‘s shortened, electronic remake of his classic song ”American Pie.” McLean said in a statement that ”her version… is sensual and mystical. I hope it will cause people to ask what’s happening to music in America.” McLean went on to say that Madonna’s version is ”a gift from a goddess.”

TUBE WATCH Carson Daly, MTV’s most popular host, is in final talks to host a program at CBS (which is, coincidentally, in the middle of merging with MTV’s parent company, Viacom). There’s no word yet on exactly what Daly would do at CBS, but the good news for teenage girls everywhere is that he will still be on MTV…. Fox’s freshman drama ”Get Real” will get another chance to prove itself. The network has ordered five more episodes of the show and will air an uninterrupted eight-week stretch of the series until May sweeps, when Fox will decide whether to renew the program for next season…. Thomas Gibson (”Dharma & Greg”) is set to star opposite ”Anna and the King”’s Bai Ling in an NBC Hallmark Entertainment miniseries, ”The Monkey King.” Gibson, who was paid $1.5 million for the role, will play a young American businessman who goes to a Chinese land to fight mythical creatures.

GOOD FRIEND After coproducing his pal Rob Schneider‘s surprise hit ”Deuce Bigalow: Male Gigolo”, Adam Sandler is ready to help produce fellow ”SNL” alum Dana Carvey‘s next project. Thanks to Sandler and his producing partner Jack Giarraputo, Carvey will star in and cowrite a comedy feature for Disney.

CASTING ”7th Heaven” star Jessica Biel has signed on to star in Warner Bros.’ ”Summer Catch,” opposite Freddie Prinze Jr.. The story is basically poor-boy townie (Prinze) meets rich girl (Biel) over her summer vacation in Cape Cod and falls in love (”Dirty Dancing,��� anyone?). The casting news comes soon after Biel, who posed nearly nude for Gear magazine, prompted ”Heaven”’s exec producer Aaron Spelling to file a $100 million lawsuit against Gear for defaming him by claiming he has forbidden Biel from doing film roles…. Diane Lane (”A Walk on the Moon”) will costar with Leelee Sobieski in Columbia Pictures’ drama ”The Glass House,” which starts shooting this spring. The drama follows a teen (Sobieski) who moves in with family friends (Lane) after her parents die in a car accident, only to discover her new guardians may have played a part in her parents’ deaths.

REEL DEAL Forget ”Phantom Menace,” here’s a prequel you could really sink your teeth into: Unapix Films will finance a pre-story to the ”Texas Chainsaw Massacre” franchise titled ”Ed Gein,” the name of the real-life serial killer on whom the movies are loosely based (”Psycho” and ”Silence of the Lambs” are also reportedly inspired by Gein). Martin Kunert (”Campfire Tales”) will cowrite and direct, with a July start date scheduled.