Longtime Batman fans can remember a similar uproar over Keaton's casting in the 1989 "Batman" film, which co-starred Jack Nicholson. Despite the furor, there's no doubt that Keaton's portrayal of Bruce Wayne / Batman set the standard for years to come.
TMZ caught up with Keaon as he as leaving Toscana in Brentwood Wednesday night. In the embedded video, Keaton can be seen saying "He's gonna be great," then repeating, "He's gonna be great."
The still untitled Batman / Superman movie is scheduled to hit theaters on July 17, 2015. Not much more is known about it aside from that, although it is rumored that "Breaking Bad's" Bryan Cranston has been signed to portray Superman's arch enemy, Lex Luthor.