Clooney's return had long been rumored, albeit wishfully, as "E.R." began approaching the end of its storied run. Those rumors have come increasingly concrete in recent days.
Citing unnamed sources, People first reported earlier this week that series executive producer John Wells was closing down the set to outsiders to keep Clooney's upcoming appearance a secret. It took all of two days, though, before Extra came through with the first picture of Clooney back in scrubs on the show's set.
Of course, both ExtraTV and "E.R." are Warner Brothers TV productions, hence the corporate synergy.
Clooney left the cast of "E.R." in 1999, but his Dr. Doug Ross made a surprise cameo in the 2000 episode that marked the end of Julianna Margulies' time on the medical drama.
The 15th and final season of "E.R." was extended last week by NBC. The two-hour series finale will now air on Thursday, April 2.
There's no word on when the Clooney episode will air.