A pair of former TV stars are returning to the small screen: Former 'Felicity' and 'The Unit' leading man Scott Foley has landed a major recurring role on 'Grey's Anatomy,' while 'That 70s Show' actress Laura Prepon will appear on 'Castle.'

Foley will play Teddy's new love interest, who also happens to be a patient at Seattle Grace. Deadline reports that it's a "major recurring role," which is usually 'Grey's' guru Shonda Rimes' way of introducing characters -- so Foley might stick around the hospital longer than your typical guest star.

Prepon, on the other hand, has been cast as Nikki Heat, the main character in 'Castle''s movie/novel-within-a-show. TV Guide reports that her first appearance will be in the Jan. 3 post-'Bachelor' premiere episode.

In other TV news ...

• Oprah is being sued by the author of a political guide. Charles Harris is accusing Winfrey of plagiarizing elements of his book during the 2008 presidential campaign by reading segments aloud on air. [THR, Esq.]

• Taye Diggs sold a drama about the "ethically complex world of adoption" to ABC. No word on whether the 'Private Practice' star will appear in his show, which will follow Los Angeles-based lawyers, doctors and caseworkers. [The Live Feed]

• Rob Schneider is returning to television with a CBS sitcom. The new series is described as being loosely based on the actor's life, and will follow a man who marries into a large Mexican-American family. [TV Guide]

• Eugene Levy and 'Party Down''s Martin Starr have teamed up for a CBS comedy. The network made a blind deal with the duo, so there's no word on what the project actually involves. [The Live Feed]

• A pair of former lost producers sold a sci-fi drama to ABC. The sci-fi/fantasy/mystery series is about modern-day fairytales in small-town Maine. [Variety]