Variety reports that George Clooney and Julianna Margulies will be featured in cameo appearances on ER.
The thespians will be reprising the roles they had in the beginning of NBC's long-running hospital drama.
Nothing has been confirmed however People magazine says that "series co-creator John Wells recently ordered a closed set for a Clooney appearance."
Noah Wyle will be coming back for four episodes as Dr. John Carter. In addition to this Anthony Edwards will return as Dr. Mark Green. His character died on the show so he will only be seen in flashbacks.