Affleck will portray the Caped Crusader in the upcoming sequel to this summer's (13) Superman blockbuster Man of Steel, but his casting has been met with fury from many comic book fans, who have even started a petition to have the role re-cast.
Franco, who played Harry Osborn in three Spider-Man movies, is adamant Affleck has proved himself as a worthy actor and director, and suggests he should even step behind the camera to take charge of the superhero film.
He tells E! Online, "I think he’s proved himself now as both a director and an actor. But I will say he’s best in the movies he directs. Maybe he should direct it. I think he should direct it... I think he'll be a good Batman."
Franco also insists fans shouldn't hold a grudge over Affleck's previous role in panned 2003 superhero movie Daredevil.
He adds, "Daredevil wasn’t my favourite movie, but I don’t blame Ben for that. As an actor, there’s this crazy thing where you could be good, you do good work, but then if you’re in a movie that’s not so good, they blame you… That’s just crazy thinking.”
Other stars who have voiced support for Affleck's casting as Batman include the actor's friend Matt Damon and his wife Jennifer Garner, as well as Josh Brolin, who was briefly considered for the role, and The Dark Knight Rises star Joseph Gordon-Levitt.