Oliver Platt will star in ABC's comedy pilot The Thick of It. The show follows the workers in the office of a low-level congressman; Platt will play the chairman of the Party Committee, notes The Hollywood Reporter.

Chris Lowell is the latest to join ABC's potential Grey's Anatomy spinoff; Lowell is set to guest star in the two-hour season finale of the show designed to serve as a springboard for a potential spinoff from the hit medical drama.

Steve Howey has landed the lead in Fox's comedy pilot The Beast, which centers on a womanizing veterinarian (Howey).

James D'Arcy has been tapped to star in Fox's drama pilot Them. The show centers on a sleeper cell of extraterrestrial terrorists who take the shape of humans; D'Arcy will play the lead agent responsible for enforcing policy.

Lacey Chabert has been cast as a lead in Fox's untitled Liz Meriwether comedy pilot, which centers on three sorority sisters (Chabert, Molly Stanton, Dorian Brown) who try to clean up their act after graduating from college.

Tim Peper has nabbed a lead in ABC's comedy pilot Carpoolers; it centers on four suburban men, one of them played by Peper, who carpool to work.

P.J. Byrne and Eric Winter have joined CBS' one-hour pilot Viva Laughlin, about a man (Lloyd Owen) who dreams of opening a casino; Byrne will play his accountant and business manager, while Winter will play a police detective.

Thad Luckinbill has been added to the cast of CBS' cop soap Protect and Serve.

Drew Sidora has been cast in Fox's dramedy Nurses.

Taylor Momsen has been added to the CW's drama pilot Gossip Girl.