Every so often rumors emerge claiming that George Clooney will finally reprise his role on ER. When asked last March if he would make a guest appearance on the show, Clooney denied it. However, it looks like this time it’s a go — People is confirming the news, adding that ER co-creator John Wells has ordered a closed set to keep Clooney’s appearance under wraps. Clooney, who played Dr. Doug Ross, was last seen on ER in a 2000 cameo in a remote lake scene with Juliana Marguilies, after leaving the show in 1999. ER has made stars of many actors, but Clooney is obviously the most famous alum ever and Wells has been hoping for a long time to have him return for the show’s last season. NBC executives announced last week that the season will be extended for an extra four episodes.