This new report also clarifies that Dwayne Johnson, who teased a mysterious Warner Bros./DC Comics project last month, will be involved in Justice League. We reported earlier this month that the actor may be playing John Stewart, a.k.a. Green Lantern, although it wasn't known if he would be playing that role in Batman Vs. Superman or Justice League, or both.
As for the news of Batman Vs. Superman and Justice League being shot back-to-back, the move was made to maximize the cast members' schedules, since Henry Cavill, Amy Adams, Ben Affleck and Dwayne Johnson are in high demand these days. Another reason is because Batman Vs. Superman will feature a cliffhanger/teaser that will lead directly into Justice League, and the studio wants to deliver Justice League in 2016, to capitalize on all the buzz that will be surely swarming around that project.
However, Justice League still does not have a director in place yet, and with Batman Vs. Superman set to start production this spring in Michigan, Warner Bros. would likely have to move fast to find a filmmaker to get this project ready in time, if it actually is set to start filming later this year.
Finally, we reported earlier today that Josh Holloway is being "strongly considered" for an unspecified role in Batman Vs. Superman, which may be Aquaman. However, while this rumor hasn't been officially debunked by the actor or anyone at Warner Bros., his schedule on CBS' Intelligence could put him out of the running for a role in the sequel, especially if the show is picked up for a second season, which seems likely at his point, as it was the most watch series debut this past year.
Batman v Superman: Dawn of Justice comes to theaters March 25th, 2016 and stars Henry Cavill, Ben Affleck, Amy Adams, Diane Lane, Laurence Fishburne, Gal Gadot, Jesse Eisenberg, Jeremy Irons. The film is directed by Zack Snyder.