Even when Nazis invade Earth-1 in this year's Arrowverse crossover, the characters of Supergirl, The Flash, Arrow and DC's Legends of Tomorrow will maintain their sunny attitudes. During a set visit, The Flash star Grant Gustin promised "Crisis on Earth-X" will "stick with the comedy we've had all year," teased Barry's upcoming nuptials with Iris West and explained why it was appropriate that the wedding takes place during the crossover event.

"It was bigger than ever. We knew it was going to be bigger than ever too. But every year, you can't really prepare yourself," he shared. "You think you're preparing yourself, knowing that the crossover is coming but it's a big thing. It's a really challenging feat. But I think this year, every year we top it. Again, we top it. There's more people than ever included, some of the biggest sequences you'll see with the most superheroes we've ever seen together at any given time. But we stick also, at least The Flash side of things, we stick with the comedy we've had all year. That still exists within the crossover. Barry and Kara have a few interactions that are fun, classic Barry and Kara interactions. I meet a couple new characters. It's bigger than ever before."

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As to Barry's wedding with Iris, he said, "It's a comic book wedding, so it's classic. It's beautiful. But obviously, things aren't going to be perfect. Something's going to happen. But it's classical, it's classic beautiful wedding. It's cool... It's on this set too that they told me how much they spent to build it but I'm not going to repeat that. It was in a warehouse soundstage, it wasn't a real soundstage. It was in this warehouse that they built a church. It was insane. You thought you were in a real church and it was beautiful. I'm excited for everyone to see it."

"We've been leading up to this wedding for a long time," he added. "It's in some ways fitting that it's part of the crossover, because it's also a little strange that we've been leading up to this wedding and it's not even on Flash, it's technically on a different show. I'm interested to see how some viewers feel about that. But it's also how this show started, this show started on Arrow. We've consistently had these crossovers and we're bringing so many characters together for this wedding, it's kind of fitting that it happens somewhere else."

This year’s four-part crossover “Crisis on Earth-X” will air across two nights, beginning Monday, Nov. 27 with Supergirl and Arrow (on a special night for one week only) and concluding Tuesday, Nov. 28 with The Flash and Legends of Tomorrow.