There's a lot happening in "Batman v Superman" so there's a lot to be unraveled in the movie. For one, a subtitle like "Dawn of Justice" tease the coming of the "Justice League" movie. But while the latter is set to start production in a matter of weeks, there's still a lot not known about what Zack Snyder's take would be.

Let's have Deborah Snyder help us out. Talking to Collider, the "Batman v Superman" producer offered a few tidbits that would help put The Flash's appearance into perspective.

In "Batman v Superman," The Flash appeared twice: once with other members of the Justice League as Wonder Woman was going through Lex Luthor's files and the other, earlier in the movie as future Flash gives Batman an urgent message regarding his notions of Superman and Lois Lane's importance.

According to Snyder, the cameos were actually not part of the original script.

"I think we were in the middle of shooting and we started working on the outline for the next movie and where they go, and Zack said, ‘Oh my God let's add this moment that is gonna pay off down the road," she said.

That means The Flash's appearance was not just a tease that they just worked into "Batman v Superman" and actually has meaning, which will probably be explained in the "Justice League" movie.

Using cameos to introduce characters is a common practice and Snyder pointed out how a "Wonder Woman" tease in "Batman v Superman" came about in a similar manner.

The daguerreotype photograph where Wonder Woman is first seen? It was shot then reshot. They were already done with it before working on the script for the "Wonder Woman" movie when they thought about working shooting the photograph into the story.

The reshoot was done while "Wonder Woman" director Patty Jenkins was carrying out camera tests so the scene will be shown when the movie hits cinemas next summer. Easter egg tip: Zack Snyder is in the background.

"Batman v Superman" drew mixed reactions but the one thing that audiences were in agreement was that Wonder Woman was a hit in the movie.

"Wonder Woman" opens June 23, 2017.