The CW shocked DC Comics fans by managing to have Justice League star Ezra Miller cameo as his version of The Flash opposite CW's The Flash television series star Grant Gustin as TV's Barry Allen in the final episode of the Crisis on Infinite Earths television event. The Flash showrunner Eric Wallace doesn't want to stop there. There aren't any current plans for Gustin to appear in the upcoming The Flash movie, but Wallace tells Discussing Film that he would like to see more DC Comics film stars appear as their iconic characters in crossovers with The CW's Arrowverse.
Reflecting on how Miller's appearance came to be, Wallace says it came to down to the wire. "Suddenly a week after that, I was on a plane to Vancouver and suddenly, I was producing that scene on set and it was the wildest thing ever," Wallace says. "Ezra was so delightful. It was such a delight to bring him into our family. Everybody welcomed him with open arms. He was so terrific to work with. Seeing him and Grant for the first time, both in their separate Flash costumes. I wish everybody could see the first take, which I saw because I was there obviously. It was electric. It was immediately obvious to everybody. It was a very small crew. It was a very closed set because we had to keep a secret as best as we could, which thank goodness we were able to. We knew from take one, which was very much full of improv and they were moving around the script, but it was so like “what’s going to happen now?” It was so unpredictable and wild that all we could do after that first take was not to burst into spontaneous applause because we had just seen something special."
But managing to get Miller's Flash into Crisis on Infinite Earths only made Wallace consider future possibilities. "It said to us, 'Huh, if we could get The Flash from the DC Extended Universe into the Arrowverse, this can open the door for other characters.' So I don’t know what’s going to happen in 2021 and 2022, things have obviously slowed down because of COVID and because of production winding down. But I would certainly love to see the Arrowverse have the Amazons and the Wonder Woman universe come to us, or Aquaman and his universe. I would love to see Cyborg. All of these things are welcomed now because of this one event, this one crazy idea that again, I’m not sure who had it, but Marc Guggenheim made that call and when he called me and said, 'How can we pull this off? I need your help' I immediately said yes. And then the rest of the incredible Flash crew because we had to film it. Even though it was appearing in Arrow, Ezra and the DC rep who was with him came to our Flash sets. It was actually filmed by our crew on our sets. And it was one of our directors in house that had to do that scene."
The Flash returns to The CW for its seventh season in January.