Longtime Law & Order: Special Victims Unit star Diane Neal is to leave the force when her contract on the U.S. cop drama ends later this year. Neal, who plays Assistant District Attorney Casey Novak, has been a regular fixture on the TV program since she joined in 2003, replacing Stephanie March. But the star is now exiting at the end of the current series, with her final appearance to air in the season finale, which will be shown next month. A representative for the show tells Tvguide.com, "Diane spent five years on SVU and was a tremendous addition to the SVU team. She is looking forward to new opportunities and she will be missed." The program's creator Dick Wolf is reportedly looking for an up-and-coming actor to fill Neal's high profile role in the show. Also, Neal's co-star Adam Beach is leaving the hit TV show as well. The actor - who plays Detective Chester Lake in the show - decided not to exercise the second-year option on his contract. He says, "I very much enjoyed my year on (the show). Now I'm looking forward to new adventures."