The latest 'Gossip': Snow in the forecast Nellie Andreeva Feb 27, 2009, ET

It seems like the "Gossip Girl" spinoff has found its Lily. Brittany Snow is in final negotiations to topline the project, a prequel chronicling the wild teen years of Lily van der Woodsen (Kelly Rutherford) in 1980s Los Angeles.

In other major pilot castings, Denis O'Hare has joined Fox's untitled Ian Biederman drama, "Maggie Hill"; David Morse has entered ABC's "Empire State"; Lloyd Owen has been added to ABC's drama "Inside the Box"; Ben Feldman has been cast in ABC's drama "See Cate Run"; and Busy Philipps, Dan Byrd and Brian Van Holt have joined ABC's comedy "Cougar Town."

Meanwhile, Chris O'Donnell has closed his deal to star in CBS' "NCIS" spinoff.

The "Gossip" spinoff centers on then-Lily Rhodes (Snow), who, after a falling-out with her parents, is forced to leave a life of luxury in Montecito, Calif., and move in with her sister Carol (Krysten Ritter), the black sheep of the family, in the San Fernando Valley.

Also cast in the backdoor pilot is Shiloh Fernandez, repped by Innovative and Untitled. He will play Owen, a sarcastic Valley punk.

Snow, who got her break as the star of NBC's "American Dreams," has gone on to appear in a series of movies, including "Hairspray." She is repped by ICM and attorney Cliff Gilbert-Lurie.

The Biederman project, from 20th and Imagine, centers on Maggie (Christina Cole), a brilliant surgeon who endures adult-onset schizophrenia but thrives.

O'Hare ("Milk") will play a top schizophrenia doctor who treats Maggie. Repped by Innovative, he next appears in "Duplicity."