From NBC today:
NBC announced that Golden Globe winner and Emmy nominee Anthony Edwards will reprise his role as Dr. Mark Greene for one episode of NBC's long running show "ER" (Thursdays, 10-11 p.m. ET/PT). Edwards will return in the episode entitled "Heal Thyself," which was written and directed by executive producer David Zabel, and will air on November 13, 2008.
The installment will feature Dr. Greene in a series of newly shot scenes that will feature other characters from the show's past while also giving insight into Dr. Banfield's (Angela Bassett) past and her experiences within the walls of County General.
"We had hoped to bring back some of "ER's" stars for the final season and think that our loyal fans will enjoy seeing some of the shows most beloved and memorable characters," said executive producer John Wells.
Edwards first appeared in the "ER" pilot and after nearly eight memorable seasons, completed his run in a highly rated episode at the end of the 2001-02 television season.