Warner Bros. has added another cast member to the upcoming superhero flick "Batman v Superman: Dawn of Justice." According to Deadline, Scoot McNairy will join Ben Affleck and Henry Cavill in an unspecified role.

Warner Bros. refused to comment on the rumored casting but The Wrap confirmed the story, writing that their source "was sworn to secrecy" and couldn't reveal any details about what character McNairy was playing.

However, there has already been a ton speculation about the casting and Screenrant.com thinks fans could see the actor as Batman's sidekick, Robin.

"An actor with his track record and pedigree isn't likely to be relegated to a minor role, so while details are being closely guarded, is it possible that Ben Affleck's Batman may have found his sidekick at last?" the site wrote.

This is definitely not the first time Robin has been rumored to make an appearance in "Dawn of Justice." Recently, "Harry Potter" star Daniel Radcliffe propositioned to play Nightwing in the reported 2019 solo Batman film, tentatively titled "The Batman."

Speaking to Buzzfeed, Radcliffe said, "If they reboot that again, I'll do that, too. It's happening isn't it? With Ben Affleck. I could be Robin. I'm perfect."

There was also a Nightwing rumor back in May when several sites reported that Robin was going to betray the Caped Crusader in the superhero flick.

"Sounds about right to me too. I once again suggest you check the NEW 54 Nightwing. This may give us clues to where they are going in the movies," MoviePilot wrote about the rumor.

In December, Latino Review also reported on the rumor and said that the two pals would have some type of falling out. Also around that time, the site tweeted a spoiler alert claiming that Batman and Robin would not be speaking to each other in "Batman v Superman: Dawn of Justice."

"Can't wait for #BatmanvsSuperman... #batfleck semi-retired/not speaking to Robin anymore... Controlling drones from the batcave," El Mayimbe, from the Latino Review posted.

If McNairy was cast, he joins Henry Cavill as Superman, Ben Affleck as Batman, Gal Gadot as Wonder Woman and Jesse Eisenberg as Lex Luthor.

The movie is slated for a May 6, 2016 release date.