Clooney's Caped Crusader became the last of several surprise cameos by legacy DC actors in The Flash, with his version of Batman seemingly replacing Ben Affleck's in Barry Allen's universe following his trip through the Multiverse.
This was only Clooney's second time playing the role after his critically maligned efforts in 1997's Batman & Robin, with the Batman legacy being explored through multiple classic actors in the Flash's first true live-action solo film.
George Clooney Shown in The Flash BTS Photos
"Happy batman day !"
Muschietti stood tall on set in front of Clooney as the two discussed his cameo appearance at the end of the film.
This photo marks the first behind-the-scenes look at Clooney's shocking appearance in the film. The first official images of his Flash character were released in mid-July, about a month after The Flash premiered in theaters.
Will George Clooney Return as Batman?
Although it appeared that George Clooney's Batman was the main version of Bruce Wayne in the DCEU at the end of The Flash, it's highly unlikely that he'll don the cape and cowl for a third time in James Gunn's rebooted DC universe.
Even with Clooney seemingly enjoying his time on set working with Ezra Miller and the rest of the Flash team, Gunn and his partner Peter Safran will assumedly want to move forward into something fresh for their new version of Batman.
Currently, the only project coming up that's confirmed to feature Batman is The Brave and the Bold, which will be directed by Muschietti himself, although no casting decisions have been made for the film just yet.
With plenty of time remaining until DC Studios moves further into its casting process, Clooney's time in The Flash will still be a popular talking point for fans as they wait for new stories to be developed.