Crisis On Infinite Earths Producer On How The Big Surprise Cameo Happened (SPOILER)

WARNING: Spoilers follow for the Arrowverse’s Crisis on Infinite Earths crossover.

Crisis on Infinite Earths had a lot of great cameos, but one came as a complete surprise and now we know how it was pulled off. In the Arrow episode of the crossover, Barry Allen (Grant Gustin) is in the Speed Force when he encounters a very different version of himself: the DC film version played by Ezra Miller in Justice League and Batman V Superman: Dawn of Justice. The cameo didn’t leak and executive producer Marc Guggenheim spoke with Variety about how the whole thing happened at the last minute.

“We were series wrapped on Arrow, and we were wrapped on the whole crossover. We were in post and some episodes were locked, and some were soft-locked. I got a phone call from [Warner Bros. boss] Peter Roth saying, ‘I know you’re locked, but can you put Ezra into the crossover?’ And I said, ‘Yes.’ And he said, ‘How, you’re series wrapped? And you’re wrapped on the crossover.’ And I said, ‘Yeah, I know, but if you’re telling me Ezra Miller can be in the crossover, I can make it happen.’ I called Eric Wallace who who is the showrunner of Flash, and he called up Grant Gustin — because the one thing that was our only concern was the thought we didn’t want to do it unless Grant was 100 percent onboard with it. And he was. He was incredibly enthusiastic and onboard with it.”

Guggenheim continued, “And then we got on the phone with Ezra Miller and told him the scene I had written and he was completely into it. And we just went. We put together a unit of the Flash crew on the Flash set [since Arrow’s team, which had produced the rest of the hour, was gone]. And much to our surprise, no one noticed Ezra Miller was in Vancouver and no one leaked it from the crew, which we appreciate. So we were able to keep it a surprise.”

Miller is set to reprise his role as Barry in the upcoming Flash film, currently set for a July 1st, 2022 release date.