The Arrowverse's biggest crossover event in history, Crisis on Infinite Earths, is nearly upon us! The sheer amount of guest stars, new characters, and new roles being introduced in this five-part crossover is enough to make anyone nerd out, but you'll never guess which twist actually had the entire cast on cloud nine.

TV Guide has spoken to several Arrowverse cast members about filming Crisis on Infinite Earths, and while spoilers are being kept under lock and key, cast reactions are decidedly less guarded. And without fail, the actors could not wait to gush about how awesome it was to see DC's Legends of Tomorrow's Brandon Routh suit up as Superman again after playing the Man of Steel in the 2006 movie Superman Returns.

"Seeing him in the Superman outfit was just — everybody just gasped," Arrow's David Ramsey told TV Guide. "Brandon looked like a Greek God. He looked like 6'6'' or 6'7'', muscles everywhere, a little grey in his hair. It was just perfect. And he just had this thing about him. His hands were always on his hips. He was golden era Superman... You think about Superman and if you say the words super man — he looked like a super man... Your eyes just couldn't get off of Brandon."

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"It was really fun watching Brandon Routh just like flip over and change over from Ray Palmer to being essentially Super-Brandon — that's what we've been calling him," said The Flash's Carlos Valdes. "It's super weird but also really gratifying to watch him play these two characters, you know? It means a lot, not just for the fans and the writers, but also for Brandon himself. I think that's part of what fascinates me about him playing these two characters is that I have to imagine there's a personal component as well. I'm just sort of caught in all the different imaginings of what this must mean for him to revisit that character while also playing out the rest of this character."

"That was one of the coolest things that I've ever gotten to do in my life, just seeing [Brandon Routh] walk out in the costume. Like, 'Holy Toledo! That's that guy, that's him,'" Hartley Sawyer added. "Brandon has a deep, deep understanding of what Superman really represents and what that character is really about, and to see somebody who plays that character so well and then to learn the understanding that he has and the thought that he's put into it? That was really cool. I kind of just bowed down before him because it was like, 'Man, not only are you so good at this, but you get it. You completely get it!'"

Judging from the photos of Routh back in the Superman suit, it's easy to understand why everyone was so wowed. He really does look like he jumped right off the cover of a comic book. We can hardly wait to see how this version of Superman will make his entrance!

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Crisis on Infinite Earths kicks off with Supergirl on Sunday, Dec. 8 at 8/7c and will continue with Batwoman on Monday, Dec. 9 at 8/7c and The Flash on Tuesday, Dec. 10 at 8/7c. The event will then return after winter hiatus for its conclusion with back-to-back episodes of Arrow and DC's Legends of Tomorrow on Tuesday, Jan. 14, starting at 8/7c.

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Grant Gustin, Audrey Marie Anderson, Caity Lotz, and Brandon Routh, Supergirl Photo: Katie Yu, Katie Yu/The CW

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